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Crossfire injection problems

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Crossfire injection problems

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 05/19/13
03:06 PM

Have an acquaintance with Crossfire problems on his 82 Vette.Intermittent Code 44/55.
Engine stumbles at constant throttle.Idle and WOT are fine.Haven't looked at it yet, but I'm thinking Ground problems.

Anyone here with troubleshooting knowledge on these crossfire systems.The only experience I've ever had with them is ripping them out when they caused flac.

The older I get,the faster I was.

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 05/19/13
06:51 PM

i have a whole LOT of experience in crossfire fuel injection systems...

you should also treat these as a CONVENTION TBI system.. there is LITTLE that is exotic except for having dual idle air control valves on the individual throttle bodies..

i have covered these so often over at corvettefever and vetteweb forums but i can cover it again ..

the 44 is a lean exhaust and 55 is i think REPLACE the ECM.. i will double check..

you will need to check a few things and have a few tools ...

digital volt meter with piercing type test clips..

hopefully a fuel pressure tester...  i don't recall of the 82 has a test port on the fuel rail .. probably.. Other TBI systems do not..   fuel pressure issues will drive you crazy..   as these are only 12 or 13 PSI... and anything less and the computer freaks out attempting to keep the idle up..

one of the neat little harbor freight amp meters that plug into the fuse block.. and measures the amp draw of the fuel pump...  restricted fuel filters or pump failures will get you an amp draw over 7 amps..   take a timing light with you.. to check the timing.. but also to aim at the fuel injector spray nozzle.. make sure you have nice cones from BOTH injectors.. even while cranking...

check for vacuum leaks.. like a bad power brake booster..

check for leaks to the MAP sensor...

do you have an OLD OTC monitor 2000 kicking around.. that or a monitor 4000/ 4000E or one of the versions that has to have the grey adaptor to go from the 12 pin monitor scan tool plug to the 5 pin ALDL connector under the dash...  and you can look at live data and shorten the diagnostic path by hours..  if NOT DAYs...  can you see the grey connector without a label at about 10 o clock in the picture.. above and left of the yellow label cartridge.. thats the 12 pin to 5 pin adaptor... craigs has some monitor 2000 models for like 50 to 70 bucks sometimes .. work great on these pre 89 models...

the snap on MT2500s also had that connector available..

with the digital volt meter.. do a voltage drop test...

20 volts DC setting.. engine running. headlights on...

1.. positive battery post to the negative battery post... 14.1 to 14.8 volts IS acceptable..

2.. Negative battery post to the engine block.... 0.04 volts MAX is accepted..

3.. Negative battery post to the body structure .. 0.02 volts MAX is accepted..

4. engine block to the body structure firewall ground.. 0.02 volts MAX is accepted..

the test above only takes about a  minute to run.. . post results by number




since  the battery might be behind the seats. if i am thinking properly.. use a single jumper cable to extend it up to the hood area without hooking it to anything up front except your test lead into the volt meter..

why.. electrons flow from NEGATIVE to POSITIVE.. no ground.. no electrons..  

there are several ground connections on the engine.. they all have to be taken off and wire brushed and reinstalled. the ECM is ONLY grounded to the engine block..

this should be the 82 crossfire wiring diagram.. you might want to print it...


grounds are at B6, B12, B13,   A15 shows as a ground... i wonder.

you will also want to print this one..



on the far right of this image blow.. is the EGR control valve.. note the ground wires for the fuel injection system are attached to the bolt next to it...

there are more ground wires stashed around the car.. and ALL ARE IMPORTANT to be cleaned..

here is a list of data stream from the 84/89 models. the 82 won't show this many...


lastly... the coolant temp sensors that are screwed into the FRONT of the intake manifold.. NOT in the heads are horrible..  replace with an SU102 from autozone or wells.. they come with a pigtail also for 3 bucks more than just the sensor..  the only difference is the type of connector... Ask for it by part number.. as they will try to sell them to you individually..  for double the money.. hmm..

lastly...  take off the distributer cap...  expose the coil.. also .. examine it for signs of high voltage leaks from the sides...

take a bright flashlight and check the sides of the pickup coil for signs of broken magnets in the stack.. the thermal soaking these get under the corvette hoods is tremendous..  if you have to pull the distributor.. please preset the crank so the rotor is pointing in the proper direction and the reluctor tips and the pick up coil tips line up perfectly without going past and needing to turn the crank backwards... then look at the timing marks.. where do they line up.. this can save a LOT of time... as they are a PAIN to get the distributer out and in..  and dead stick timing it works great...

sorry if i have bombarded you with info...  i went to GM training school on feedback carbs and these throttle body fuel injection and also port fuel injection systems..

if you get in trouble.. check your private message...  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 05/19/13
07:11 PM

these images are for the 84 models. but are almost identical to the 82 models.. 82 models used an earlier computer than the 84s did..



su102 coolant temp sensor kit


this is probably an 84.. i don't think the battery is in this location.. i usually work on C4 versions.. not the slightly earlier 82 crossfire versions...

please look at all the ground connections that you have... and they ALL GO TO DIFFERENT circuits.. they all have to be intact...

82 84Crossfiregroundconnection  

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 05/20/13
03:08 AM

Thanks Wayne,

If he manages to bring it by,I'll check out what you've sent me.

I was thinking.He said it runs like a tractor at idle and constant throttle,back fires under mild acceleration,but full throttle is fine.I had that also once or twice with a few "normal" motors.It was on each occasion the mechanical advance
was toast.Could cause the code 44?The fuel is not burned completely,the ECM see's this and try's to so long to correct it until a lean condition is present,hence 44.Or the ECM is trying to correct a mechanical defect and can't,so "I must be broken" code 55?
Only speculating .Will know more if/when he gets here  
The older I get,the faster I was.

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 05/20/13
08:36 AM

the checks above first....

without a scan tool... you will want to do some mechanical checks first..

things to check... for a code 44...

find the air injection check valves.. these are tubes that go into the exhaust manifolds...

disconnect the rubber hose into the check valve...  plug the check valve opening...   plug one of the hose openings...   with a friend at the ignition key.. place the finger over the end of the disconnected hose...  so you can feel flow or no flow..

have the assistant start the engine... for the first 15 or 20 seconds you should have flow from the diverter valve into the UPSTREAM air tubes..  then it should shut off...   if you rap the throttle .. the upstream air should again flow for a few seconds.

let me explain... as this can happen to a LOT of cars.. and drive techs crazy..

the oxygen sensor.. is infront of the cat..  usually on later models right in the exhaust manifold..

the air injection adds commanded air during OPEN LOOP to create combustion in the exhaust system to warm the oxygen sensor and the cat..   the air injection is also commanded on during medium hard to hard throttle application when the system jumps out of closed loop and into open loop..  to burn off excess hydrocarbons..

if the air injection diverter valve has failed... and is allowing uncommanded air into the upstream exhaust.. there will be TOO MUCH OXYGEN there  and the oxygen sensor will really screw with the air fuel ratio trying to correct it..

leaks in the exhaust... leaks in the air injection system. including rusted out check valve bodies..


next.. lets see if the cat is clogged... with a vacuum gauge hooked to manifold vacuum...   slowly increase the engine rpms up to around 3000 or 3500...   the vacuum should NOT DECREASE...


now.. with a digital volt meter..   hook up and pierce carefully.. as the oxygen sensor is under the passenger side of the car.. and you don't want to ruin the wiring insulation ..  hook up the digital volt meter and monitor the voltage at idle.. use 2 volt DC scale.. it should switch from 0.1 to 0.8 or 0.9 volts constantly... take the RPMs to 2500 with a helper and hold the pedal steady.. still should have a constant swinging...  this is best looked at with a hand held digital scope.. but i don't expect everybody to have one.. its sometimes just easier to purchase another oxygen sensor and screw it in..  they do wear out and get contaminated..

lastly.... that computer is probably 30 or 31 years old....  do you have any experience in resoldering circuit boards?? i do them all the time...  but i use solder that does contain lead.. not the lead free stuff..  SN62, SN63 or SN44..  rosin core.. NOT ACID CORE..  with a big magnifying lens with enough light or jewelers glasses..  a  fan blowing across the work area as you don't want to breath the fumes..

here is what to look for... and this is just a honda main relay..


warning.. static discharge is a bad thing..   20,000 volts into a circuit that blows out at 18 volts is a bad idea.. . so always touch a ground on the circuit board first..

you will also want to ohm your soldering pencil... or soldering station.. NO CONTINUITY between any of the power terminals and the tip of the unit...  if you have continuity between the tip and any of the power terminals. please don't use it.. 120 volts or 240.. i don't know what you have there will COOK digital electronics..   my older brother taught me how to solder properly..  

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 05/20/13
10:15 AM

Not a problem Wayne,
Don't want to ring my own bell,but..
I went to automotive tech school at Bee county Jr. College from 83 to 87.Got my bachelors in automotive engineering..... joined the military in 88 and never got a chance to use it.Did heavy wheel / track maintenance for Uncle Sam.Stayed in Germany after my discharge and worked building hydraulic and pneumatic systems for power take off systems on Semi's.When my back gave out Germany sent me back to school to learn Industrial Electronics.Been working the last ten years in customer based electronic design,and repair.

All my soldering and measurement equipment is potential free.And I have an ESD protected workspace. Grin

This guy told me today that he had the ECM open,and replaced 2 resistors that were burned up.I told him that resistors don't just burn up out of the blue and that this was an effect of something pulling to much current.He also had no idea what values the burned ones had.He just replaced them with any old ones he could find.I have no earthly idea where to get the schematic for this ECM so I told him he needs to get another and we'll go from there.

Don't ya just love trying to fix things,not knowing "Bubba" was there first.This should be the first step in any trouble shooting action.Ask,"Was Bubba here?"

I have all the info you gave me stored on my HD for now, and if a new ECM don't fix things then at least I have a starting point.That with the A.I.R system is a very good place to start.
Thanks for your help and suggestions.

The older I get,the faster I was.

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 05/20/13
11:24 AM

in all the years i have been around.. i have never seen a circuit board schematic..

comparing to a good unit only..

ohm each of the controlled circuits right from the ECM connector.,.

nothing less than 20 ohms other than the injectors at 1.2 or 1.3 ohms..

could also have broken insulation in the twisted pairs to some of the devices..

check the link i sent you in the private message..

it will have more info that you can use for minimal cost..

i don't have any of these units to compare...  or examine right now...  can you supply the 122XXXX numbers off the ecm?

i have a friend with a junk yard here who might have one i can open and take a high res image of the circuit boards...

its not that hard to strip out the crossfire harness..  under 2 hours... to check it on the bench..

some people have swapped to the C4 crossfire harness ... sensors are the same.. for the most part..  only the connector for the ECM is different and the way it hooks to the car harness under the dash as there is a 12 pin aldl instead of a 5  pin. version..   one can probably cut the harness end off any GM TBI or PFI car that matches the 84 computer and splice it in... tap it in and have a separate ALDL for the 84 computer right near the ECM.. where its still accessable...

there are a LOT of people who have gone a LOT newer like 87 88 model year TBI computers ... but i don't know how they work the double idle air control valve operation..  

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 05/20/13
03:19 PM

When I said "Acquaintance",I meant some one I met a few years back and haven't heard from since.I've never even seen his car, so I have no idea what to expect,if he even brings it over.I offered him my, your,our help.I translated and relayed your info this morning and ain't heard nothing yet.Today is a holiday here.Let me see what he comes up with over the next couple of days,and go from there.

The older I get,the faster I was.

stillakid stillakid
I love my Chevy Chevette! | Posts: 1 | Joined: 08/13
Posted: 08/04/13
10:51 AM

Glad to find someone familiar with cross-fire injection. I have a 1982 Collector Edition Corvette with cross-fire injection. It's been sitting in a museum for 7 years. Just before I took it to the museum it started having an intermittent problem with the injection system. You could be driving down the road, and all of a sudden, the motor would run rough. This might last anywhere from 2 minutes, to 30 minutes. I tracked it down, and what is happening is the injector on the driver side quits working. I get my voltage meter, test the wires going to that injector....and no voltage. Then, it will eventually start working again. Test with a voltage meter, and I have voltage. I bought a Haynes manual for my Vette, to try and get some trouble-shooting ideas, and all it says about cross-fire injection is...take it to an authorized service tech. Oh, and when the engine is running rough,  the Check Engine light does not come on!! Before I take it to the dealer AND PAY BIG BUCKS , can someone give me some troubleshooting tips? Confused  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 08/04/13
11:43 PM

autozone covers the crossfire in 3 different sections..

82 corvette

84 corvette

83 firebird

each section for some reason is slightly different..

you can get a manual for your corvette.. they are available for not a lot of money..

i would start with an decent DIGITAL VOLT meter..  that has a 15 or 20 AMP DC setting.. grab a TBI injector pigtail from the junk yard.  

you will need to set it up like this...

pigtail.  wire..   momentary push button, normally open..   wire..   battery clip..

pigtail.  wire..   banana jack /CUT/  banana *** wire.. battery clip..

what this is going to allow you to do.. is stick the banana jacks into the 10,15 or 20 AMP DC jacks on your digital volt meter.. amp jacks use the same common. but a different jack for the 10, 15, 20 amp positive..

now.. with the banana jacks plugged into the proper amp meter ports on your meter.. the injector plugged in..  then hook up the battery clips..     watch the meter..  push the button for NO LONGER THAN 7 seconds..  what does the AMP DRAW do.. it should start high and drop..  NO LONGER THAN 7 SECONDS..

test the other injector.. they should be the same..

why spend this time for 14 seconds worth of testing.. because TBI injectors sometimes SHORT internally.. look fine.. ohm fine.. but this AMP load test stresses the coil windings and if they are going to short out.. it will have an INCREASING AMP draw..   you might want to put a 10 amp ATO fuse inline ..

next.. some parts stores have NOID lights or injector test light sets in the LOAN a tool section.. harbor freight also sells a set.. you can unplug the injector and hook it right into the pigtail crank the engine and see if you get a nice flashing light..

look at the wiring diagram above..  print it..  

which wire is intermittent.. ..

don't forget to check out the corvettefever and vetteweb forms.. i have posted stuff in both of those also..  mostly under the C4 area.. but there are a few in the C3 areas..  

waynep712222 waynep712222
V-6 Camaros rule! | Posts: 122 | Joined: 03/13
Posted: 08/04/13
11:54 PM


looking at the wiring diagram above..

the red wire and the white wire running to the other injectors are HOT all the time.. i wonder about that..  they are on DIFFERENT FUSES also.. please check your fuses.. that the surface of the fuse and the surface of the terminals in the fuse box don't have any corrosion..


the NEGATIVE side of the injectors are controlled by the COMPUTER.. it pulls them to ground in very short pulses to create the spray..

hint.. if your digital volt meter reads MILLISECOND scale.. MS..

hook that to either the Light Blue or the Light green wire.. one at a time.. the other lead on your meter either hooked to ground or the other wire on the injector..

1.2 to 1.4 MS at idle is expected..

with an 82.. you will want to examine the inside of the computer for bad solder joints..  

monitor the voltages to the various fuses while somebody slowly rocks the ignition key from lock to on to crank and back to ON..  ignition switches have also gone bad..

i am also aware that once in a great while.. fuel pressure issues will cause TBI motors to act very strange...  

Joe747 Joe747
I love my Chevy Chevette! | Posts: 1 | Joined: 11/13
Posted: 11/21/13
08:55 AM

I'm a driver not a mechanic so, I hope I never have to replace one but, I am considering buying a 90 Vette with 44,000 miles. Should I be concerned about the crossfire injection? Thanks for any advice.  

wayne712222 wayne712222
V-6 Camaros rule! | Posts: 60 | Joined: 11/13
Posted: 11/21/13
06:10 PM

joe.. the L98 engines have just as many issues... if not more than the crossfire motors that were only available in corvettes in 82 and 84. there were no 83 models..

the 83 and 84 camaros and firebirds also used crossfire fuel injection..

joe . look over at the corvettefever forums for C4 posts with several replies..

C4's are a wonderful car. but if you are buying a 90... don't forget that its already 23 or 24 years old.  and even if its low mileage.. its going to need some lovin done to the various parts..

click my user name for a link to that magazine..  your current user name and password work there also..  

wayne712222 wayne712222
V-6 Camaros rule! | Posts: 60 | Joined: 11/13
Posted: 11/21/13
06:13 PM

one thing.. since few people have the proper scan tools for these..

verify that when you turn the key on.. that the chcck engine light comes on for 3 seconds when you start the car.. then goes out.

anything and everything on a corvette is expensive.. or a pain to rush to work on.. take your time.. have a factory service manual.. about 120 bucks.. and it won't be hard...  

Ino Alexanderr Ino Alexanderr
I love my Chevy Chevette! | Posts: 1 | Joined: 02/14
Posted: 02/17/14
01:05 AM

Hey i just saw this thread, I'm having problems with the CFI system in my 83 daytona 500 trans am... i cannot figure it out for the life of me. I replaced the TPS because the engine threw a code for it, the engine will start and run basically trying to catch up with itself until it dies. after replacing the TPS i didn't see anymore codes pop up but still the same problem... it will back fire as well the stream from the throttle bodies seems consistent when it runs for that few seconds until it sputters out and dies, everyone else have told me vacuum leaks but I've had vacuum leaks on my 94 z28 (before i sold it to buy this) and it still ran just not smoothly. i am borrowing a car right now and have to get this fixed ASAP. The guy who i bought it from said it ran and i questioned why he brought it over on a trailer... now i know why. TPS is at .05 volts tested on a dc setting i cleaned out the throttle bodies pretty well to, I don't know what it could be apparently this motor has a million vacuum lines i don't even know where to begin I'm so frustrated! help!  

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