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Ruff idol, won't run past idol without the engine dying. 90 Corvette

 
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/23/14 03:15 AM

i am taking that you changed the fuel filter..


checked the fuel pressure..   38/39 psi key on engine off..  there are several ways to turn on the fuel pump circuit.. but the pressure should build instantly..


do you have a massive vacuum leak..

do you have a massive air leak between the MAF sensor and the front of the throttle body...

can you pull the fuel pressure regulator vacuum hose off and have somebody cycle the key on a few times.. make sure the fuel pressure regulator is NOT leaking thru the diaphragm..

would you like to spend a few minutes and check the grounds..

can you disconnect the Power brake booster vacuum hose and plug it off. then try the engine..

i dont have any better connections for the 12 pin to usb... i did see the 12 pin to 16 pin obd2.. that looked interesting at 7 or 8 bucks..


oh... how about this.. perhaps you find some wiggle room in their price.. as that one won't really do OBD2.. most of those were traded in for the next model with removable cables from the top of the scanner..

http://sfbay.craigslist.org/pen/tls/4366312615.html


these work also.. but i cannot see what cables and cartridges he has with it..

http://sacramento.craigslist.org/tls/4338946189.html
they are no longer supported by snap on as i understand.. so very hard to get anything for it..  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/23/14 03:21 AM

sometimes its the smallest detail that takes the whole system down.. this is not on a corvette.. but it took several hours of work to find this exact intermittent short to ground.

1395517593374 Zps2900fbc7  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/23/14 03:33 AM

you might want to start with cleaning G101 thru G109..

C4groundlocationsbetter Zps4d7297df

you will probably want to also inspect and clean the G400 ground connector buss bar... its back by the left rear tire.. out of view.. open image in a new window..

thats the ground for the fuel pump and tail lights.


oh that looks ok.. right..

Gm Ground Buss Zps90cb8fe0


not..

Gm Groundbusscorrosion Zps3ec9ae3a  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/23/14 10:59 AM

its running..

it has no horsepower...  won't rev over 1500 RPM..

fuel issue..

clogged exhaust..

again.. do you have a vacuum gauge to check the manifold vacuum.. see if the vacuum rises as you increase the engine speed.. it should.. if it drops as you slowly increase the engine speed.. you have an issue.. with a blocked exhaust..

Fuelpumpvacuumtester  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/24/14 02:59 PM

LOG in.. check for private messages just to the left of where you log out..  

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JW72
I love my Chevy Chevette!
Posts: 21
Joined: 03/14
Posted: 03/24/14 06:44 PM

March 24, 2014


Wayne,

    I got frustrated about my 90 Corvette, talked to a couple of my racing buddies, took the Corvette down to the local Chevrolet dealership.  Although a couple of my buddies had hand held OBD I scanners, the logic was that a dealership would have a commercial diagnostic machine. I was promised a complete diagnostic testing that would detail any and all problems with a written estimate for repairs, for a charge of $140.00.  After two and a half days, I received a phone call from the dealership that they have not found the problem and that more diagnostic testing would be required.  Estimated time required to be 3 to 4 hours, guesstimate of $400.00 - $500.00.  
    When I went to pickup my Corvette I requested a print out of the diagnostic test that the dealership had performed.  I was told that what was on my invoice is the results for the diagnostics performed on my Corvette, I was told by the service rep that the dealership "technicians used a hand held scanner".  The invoice stated "Inspected secondary ignition components.  Vehicle has wrong spark plugs ( I install a set of E/3 a couple of weeks ago) Scope reading find #6 weak kv readings, compression for #6 is 175psi, all fuel inj. Ohm check 16.4 - 16.6 ohm's.  Need more diag time, suspect large vacuum leak causing lean condition".  
    What ?????   For christ sake I could have purchased a Innova 3120 Diagnostic Tool Kit OBD1 OBD2 for $130.00 and found out more information.  Large vacuum leak ????  In the head of the dealership so called technician !  My 1990 Corvette only has 48,610 miles on it.
    I can't believe this, as I drove to my home, a mile away from the dealership, my Corvette spewed smoke out the exhausts like I was on the neighbor mosquito patrol !!!  
    I feel like I wine and dinned a female and at the end of the evening I was left standing alone, holding on to my ..... !!!!!

    So, for me, it is back to the drawing board, ground zero.  I have made hard copies of all of the information that we have discussed and will start all over, with a clear head, additional information and a fresh start.

   Thanks Wayne for all of your help.

    A very frustrated,   JW

    Large vacuum leak, was that because I removed the air filter and ducting ??????  
Retired, raced Corvettes in SCCA for 20 years. Own a 1990 Corvette and a 1979 Corvette.

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/24/14 10:55 PM

ow... impressive.. now you know why i try so hard to help corvette and other fuel injected car owners..

What color is the SMOKE...


black...

white...

grey..

warning.. the innova kit only gets you codes..  not live data.. i checked..

i should get a newer small car.. just enough to toss a bag of tools in. and travel the west..  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/24/14 11:11 PM

how far are you from diamond spring???

one of the best mechanics i ever met has a shop up there. he must be 80 if he is still around..

http://www.ncpmotors.com/

http://www.mtdemocrat.com/news/norm-sappenfield-hot-rod-guy-still-making-souped-up-engines-at-age-84/

so he is still around..

he was friends with a good friend of mine who did upholstery..  people used to ship their cars up there from LA to get them fixed..

i started a engine that he built for a 59 caddy.. it was so smooth it was like an electric motor..  

he probably won't remember me.. i was just beginning my automotive career when he moved away. i was just tearing up the streets with my almost uncorked 66 GTO over at picketts shell station.  

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/24/14 11:30 PM

oops...  he only takes referred customers..

guess its up to you and me..  

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JW72
I love my Chevy Chevette!
Posts: 21
Joined: 03/14
Posted: 03/26/14 04:41 PM

Wayne,  

What Color Smoke ?    Bluish White   I did a compression check, all are around 165 lbs.  This Corvette sat for total of 16 years, the engine compartment shows severe deterioration around wire connectors.  I suspect the valve guide seals.  Compressed air to hold the valves in place, spring compressor to remove the valve spring retainer, replace seal, job completed.  Sounds easy !!!  Gee, I'm almost done.

Hand Held Diagnostic Unit  The Innova 3120 Diagnostic Tool Kit OBD1 OBD2 is just a code reader.  The Innova 3140 Diagnostic Scan Tool CAN OBD2 & OBDI, does perform live data, but only in OBD2.      Turner Pro Advanced Automobile Tuning Software is a software that works only on OBDI, you need a laptop, Windows and a data cable.  It performs live data with graphics that looks like a engine dyno.  I will have to order a data cable, OBDI 12  pin cable with a preferred USB end or a 9 pin serial port for my laptop.  Then there is shorting out ALDL pins A & B, watch the light on the dash blink 20 or 30 times.  This may cause one to have a stroke or loss of eyesight.  Nuts, I forgot, my 1990 Corvette has the Selective Sports Ride Option.  But wait there might be hope yet.  With the interior redesign in 1990, Chevrolet added additional computer capability. The CCM (Central Control Module) was added and a method was provided to display codes on the speedometer of the Corvette.  From 1990 through 1993, you shorted ALDL pin "G" to "A" and turned the ignition to "On" without starting the engine.  This action will cause the speedometer and trip odometer to become a troubleshooting aid.  

NCP  Motors- Norm Sappenfield  Excellent suggestion and possible contact.  I will give him a call.  Diamond Springs, CA, is 45 miles north of were I live.  

I have been considering my plight with my 1990 Corvette, TPI has many problems, possible electrical problems, smoking due to bad valve guide seals, needs the fuel injection nozzles replaced, check fuel system for dirt and blockage, the damn engine won't pull more 4,500 rpm.  

Hummm, were to start.  Remove the engine, install injection nozzles, remove heads and rebuild them, may as well install a high performance roller cam with roller rockers, port the heads and intake, install a larger Throttle Body, have I forgotten anything ?  Remove the engine ???  The clam shell hood weighs a ton.  Oh, Hell, I'll just park it on my patio in front of the brick BBQ and use it as a picnic table.  I have 5 1984 - 1988 Chevy TPI's, all in basket case status.  I can do porting and polishing.

Worry, worry, what to do, what to do.  Maybe I should consult my personal adviser, Mr. Budweiser.

Think I'll locate and order a OBDI cable first.

JW  
Retired, raced Corvettes in SCCA for 20 years. Own a 1990 Corvette and a 1979 Corvette.

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 03/26/14 11:29 PM

i don't know why it smokes .. yet..   bluish white.. ????

i am expecting that you have removed the fuel sending unit and/or suctioned the tank completely DRY.. thru the filler neck..  jacking the car up on one side and  extending the suction hose to the low side..

i got called to a shop many years ago.. car that smoked.. like a navy destroyer putting up a smoke screen..

i said.. dirty fuel..   hooked up the carbon clean machine with fresh gasoline i supplied and in 2 minutes it ran smoke free... told the tech to drop the tank..  blow out the lines.. drain it and reinstall the tank. use fresh gas and that should be it..

2 days later .. still smoking.. i go back.. they said they followed my instructions and it still smokes.. i ask for the gasoline they took out..  the tech said he had disposed of it..  WHERE.. i don't see it.. did you pour it in another car.. did you pour it somewhere else.. i stood on the techs toes.. leaned him backwards over the fender.. where is it.  he finally admitted.. it looked good.. so we put it back in tank.. .. at that point the car owner showed up.. the bosses brother.. i ask him just what happened.. when this car started smoking.. he said he had put 5 bucks worth of gas in it.. .. i said how much did you have.. about a quarter of a tank..  so thats about 5 gallons altogether . i stood on his toes and leaned him back over the fender.. and what else did you do ..  did you put in anything.????  weeelllll.. a bottle of fuel injection cleaner..   i leaned in farther.. how many.. FIVE... you put 5 bottles of fuel injection cleaner into 5 gallons of gas and you want to know why it smokes..

this car had been in the shop for a month.. they had gone thru 3 sets of fuel injectors.. 2 valve jobs..  a fuel pressure regulator.. a computer..  there actually was an issue with the car.. it had been in an accident previously.. and the grommet where the fuel injection wiring harness went thru the firewall had been left out by the body shop..  the harness insulation had been cut by the sheetmetal and it would stall..  it was not a visible problem and only spotted by me while i had the carbon clean hooked up.


i personally DON'T think a TPI motor is really going to pull hard above 4500 RPMs.. they are not designed to...

get  the plug.. or figure out how the CIC works to give you access to the fuel injection info..

i don't have any corvette factory service manuals as i can usually get by with my drivability manuals and 3 decades of experience.. i even looked around alldata and i could not see the CIC access info..  i know it exists as i have done it before..  years ago..  i had a half drawer of info printed out from various sources so when i needed a diagnostic set of pages i did not have to print them i could just shuffle thru and find the right section..  until my boss went on a cleaning spree.. tossed them all out.. how dare i store stuff in his filing cabinet..  he only used 3 drawers out of 5..  and i even labeled it..  


BUD WISER... don't know him..  he did make a steer at my brothers ranch extremely tasty..  darn steer would drink my brothers beer right off the fence post..  when he got invited to dinner the hard way.. we had to go back and relabel all his packages....   so far i have not found a rancher  who wants to make some bud ribs. bud steaks..  bud burgers..  they think its a waste to let the cattle drink all the bud..  you would think i was offering them a coors.. or something.  Laugh  

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JW72
I love my Chevy Chevette!
Posts: 21
Joined: 03/14
Posted: 04/01/14 02:42 PM

Wayne,  

I have ordered a OBD 2 unit, cheap, cheap, OBD 1 to OBD 2 cable and a software program that covers OBD 1 and OBD 2 that includes a OBD 2 to USB cable.  Since I don't anything about OBD 1 or OBD 2,  I have this idea to use my laptop to test both of my OBD 1 and OBD 2 cars.  The OBD patch cable is to be able to use my laptop for both.  The cheap OBD 2 unit is to introduce me to OBD 1 & 2 and to see if the OBD patch cable works.  Not sure if a OBD 2 will read OBD 1, time will tell.

Here we go again,  I talked to a friend of mine Crew Chief, about my Corvette problems.  To witch he was certain that I have the small TPI HEI with the external coil.  That would be wrong, as I have the HEI with the coil built into the cap.  Anyways, he was talking about replacing the Distributor Pick-Up Coil module, that the distributor had to be removed for replacement and be sure to clean the screens at the bottom of the distributor housing.  That would be correct.  He also suggested that I replace the oil pressure switch, if defective this would not allow the distributor to receive a electrical current, oil pressure has to be + 4 lbs.  The engine does start and idle, with a mis, but while I have the distributor out I may as well replace it.  In the days of distributors with points and external coils, yes I have had coils over heat, even leak and fail.  Car runs, coil over heats and stops, cool down, runs and stops. I have already replaced the Ignition Module and I thought the Ignition coil was just a contact gear for electrical current.  The junk yards are full of HEI units, easy to find Accel modules.  I have used HEI's for years without any failures, I have several Accel / MSD HEI units, all have been set up for racing.  

I have made up my mind to resolve my issues with my Corvette by myself, and with your help !!!!

Let me know what you think about the Distributor Pick-Up Coil module, oil pressure switch and my OBD idea.

JW  
Retired, raced Corvettes in SCCA for 20 years. Own a 1990 Corvette and a 1979 Corvette.

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JW72
I love my Chevy Chevette!
Posts: 21
Joined: 03/14
Posted: 04/01/14 02:55 PM

Wayne,

Forgot a question.

I am going to replace the fuel injection injectors.  Stock is 19 - 20 lbs.  Thinking of using 24 lbs injectors.  A little more HP ?

JW  
Retired, raced Corvettes in SCCA for 20 years. Own a 1990 Corvette and a 1979 Corvette.

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wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 04/01/14 03:39 PM

good point... there is a far better design...

BOSCH III..   cleaned match flowed sets are available from one of the suppliers... they are used in a few years of mustangs..  i forgot the exact app..

somebody lined up all the different injectors on one of the flow benches .. and video taped them at different pressure and different pulse widths.. the bosch III design never failed.. let me see if i can look it up..


here is one source...
http://fuelinjectorconnection.com/shop/viewcategory.php?groupid=101

https://www.youtube.com/watch?v=VfynoxL2RZI


https://www.youtube.com/watch?v=7oTirEZNRw8  

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JW72
I love my Chevy Chevette!
Posts: 21
Joined: 03/14
Posted: 04/02/14 12:51 AM

Wayne,

Looked at all of the websites, very impressive and informative.  I had in mind to use Bosch EV1 Design III, 4 way spray. 24 lb.

After watching youtube, I think that 24 lb injectors maybe just a waist of fuel.  Go back to 20 lb injectors?

JW  
Retired, raced Corvettes in SCCA for 20 years. Own a 1990 Corvette and a 1979 Corvette.

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