Help identifying engine and stalling-issue
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
tp
Folks,
Some years back, my dad bought an 81 Corvette that he has since stopped driving. Instead of having it sit in a garage, I've decided to show the old girl some love and fix'er up a bit.
Anyway, here is the situation; the car hesitates when accelerating from stop and stalls when approaching red-lights and I'm trying to troubleshoot the issue. However, somewhere along the line (before my dad bought the car) it has had an engine / transmission swap and I honestly have no clue which engine it has now. It is a TPI, so definitely not the original engine - but I'm having a hard time nailing it down based on casting numbers.
Do you guys have any tips on which parts' casting numbers I should be looking at in order to identify the engine? It may not be necessary to find the exact model, but based on what I've read on the forums, hesitation/stalling may be caused by different problems based on engine model.
I've posted some pictures of the car and engine which you can find here:
https://picasaweb.google.com/1015446...eat=directlink
Edit: Fixed link to pictures
Any help is greatly appreciated
Some years back, my dad bought an 81 Corvette that he has since stopped driving. Instead of having it sit in a garage, I've decided to show the old girl some love and fix'er up a bit.
Anyway, here is the situation; the car hesitates when accelerating from stop and stalls when approaching red-lights and I'm trying to troubleshoot the issue. However, somewhere along the line (before my dad bought the car) it has had an engine / transmission swap and I honestly have no clue which engine it has now. It is a TPI, so definitely not the original engine - but I'm having a hard time nailing it down based on casting numbers.
Do you guys have any tips on which parts' casting numbers I should be looking at in order to identify the engine? It may not be necessary to find the exact model, but based on what I've read on the forums, hesitation/stalling may be caused by different problems based on engine model.
I've posted some pictures of the car and engine which you can find here:
https://picasaweb.google.com/1015446...eat=directlink
Edit: Fixed link to pictures
Any help is greatly appreciated
Last edited by beernut; Aug 1, 2011 at 06:35 PM.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
Ok, so I've spent a few hours with the car tonight and have come to the (correct?) conclusion that this is a CFI engine that has had a TPI conversion done. Judging from pictures found online from other such conversions, they look very similar to what I have under the hood
Now, after digging around I have a few questions I hope you guys can help me with
The car idles a bit rough, dies at redlights and hesitates when accelerating from a stop. There are several things suggested on the forum that could be possible culprits (vac leak, IAC issues, TB cleaning etc.) but as I'm a noob mechanic, I could sure use some help...
Anyways, this is a long ramble but I hope someone can shed some light on the questions
Thanks in advance!
Now, after digging around I have a few questions I hope you guys can help me with
The car idles a bit rough, dies at redlights and hesitates when accelerating from a stop. There are several things suggested on the forum that could be possible culprits (vac leak, IAC issues, TB cleaning etc.) but as I'm a noob mechanic, I could sure use some help...
- The PCV on the driver's side is loose...that is, I can pull it out with very little effort...I'm assuming it shouldn't be like that? Could that be the cause of a vac leak? The valve seems OK (it "clicks" when shook.) The PCV is visible in this pic: https://picasaweb.google.com/1015446...96760555258594
- Is it indeed possible to remove the IAC for cleaning without removing the TB?
- I've read that a proper TB cleaning (using TB-cleaner spray) can help with idle / stalling issues. Can this be done safely with the TB still attached or should I remove it before attempting to clean it?
Anyways, this is a long ramble but I hope someone can shed some light on the questions
Thanks in advance!
Last edited by beernut; Aug 1, 2011 at 06:00 PM. Reason: Added link for PCV pic
Pro
Joined: Aug 2010
Posts: 632
Likes: 38
From: Roseville CA
Folks,
Some years back, my dad bought an 81 Corvette that he has since stopped driving. Instead of having it sit in a garage, I've decided to show the old girl some love and fix'er up a bit.
Anyway, here is the situation; the car hesitates when accelerating from stop and stalls when approaching red-lights and I'm trying to troubleshoot the issue. However, somewhere along the line (before my dad bought the car) it has had an engine / transmission swap and I honestly have no clue which engine it has now. It is a TPI, so definitely not the original engine - but I'm having a hard time nailing it down based on casting numbers.
Do you guys have any tips on which parts' casting numbers I should be looking at in order to identify the engine? It may not be necessary to find the exact model, but based on what I've read on the forums, hesitation/stalling may be caused by different problems based on engine model.
I've posted some pictures of the car and engine which you can find here:
https://picasaweb.google.com/1015446...eat=directlink
Edit: Fixed link to pictures
Any help is greatly appreciated
Some years back, my dad bought an 81 Corvette that he has since stopped driving. Instead of having it sit in a garage, I've decided to show the old girl some love and fix'er up a bit.
Anyway, here is the situation; the car hesitates when accelerating from stop and stalls when approaching red-lights and I'm trying to troubleshoot the issue. However, somewhere along the line (before my dad bought the car) it has had an engine / transmission swap and I honestly have no clue which engine it has now. It is a TPI, so definitely not the original engine - but I'm having a hard time nailing it down based on casting numbers.
Do you guys have any tips on which parts' casting numbers I should be looking at in order to identify the engine? It may not be necessary to find the exact model, but based on what I've read on the forums, hesitation/stalling may be caused by different problems based on engine model.
I've posted some pictures of the car and engine which you can find here:
https://picasaweb.google.com/1015446...eat=directlink
Edit: Fixed link to pictures
Any help is greatly appreciated
I had a stalling problem when pulling up to a stop a year ago when the intake manifold had a leak.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
Thanks for the tip!
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
I'll check the intake manifold for leaks as best as I can though, thanks for the tip!
Instructor
Joined: Sep 2007
Posts: 198
Likes: 0
From: Colorado Springs Colorado
Find where the computer is mounted on the car, then follow all the wire harness's to see where they end. Once you find the harness with the ALDL on it, post a picture of it and we'll know if it's OBD-1, or OBD-2, and can tell you how to retrieve your codes. Even though it's pieced together, the ALDL is usually put under the dash somewhere under the steering column, for ease of access.
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
Thanks again for the info - it is much appreciated
Unfortunately I ran out of time this evening so I still haven't had a chance to look for the computer. I did however go through most of the vacuum lines to check for any bad connections etc and found the PCV grommet to be bad - replaced that but no difference in operation.
Just for the hell of it, I recorded a couple of videos of the car hesitating. Strange enough it now also had a very rough idle when warm, which is a new symptom.
Hesitation: http://youtu.be/1mkTWiXfPl8?hd=1
Rough idle: http://youtu.be/cqK3dw2VWT4?hd=1
Not sure if they'll offer any more information before I locate the (possible) ALDL.
Thanks again for your input
Unfortunately I ran out of time this evening so I still haven't had a chance to look for the computer. I did however go through most of the vacuum lines to check for any bad connections etc and found the PCV grommet to be bad - replaced that but no difference in operation.
Just for the hell of it, I recorded a couple of videos of the car hesitating. Strange enough it now also had a very rough idle when warm, which is a new symptom.
Hesitation: http://youtu.be/1mkTWiXfPl8?hd=1
Rough idle: http://youtu.be/cqK3dw2VWT4?hd=1
Not sure if they'll offer any more information before I locate the (possible) ALDL.
Thanks again for your input
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Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
Check the fuel pressure. As it must have an add on pump to give enough pressure for the injection. Does that setup have a MAP sensor or some kind of mass airflow sensor? It could cause all sorts of problems with the mixture. Run some injector cleaner through the gas tank. Get it out and drive it hard a little to clear out the cobwebs. Lots to do and so little time...
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
Check the fuel pressure. As it must have an add on pump to give enough pressure for the injection. Does that setup have a MAP sensor or some kind of mass airflow sensor? It could cause all sorts of problems with the mixture. Run some injector cleaner through the gas tank. Get it out and drive it hard a little to clear out the cobwebs. Lots to do and so little time...
I did add injector cleaner today though and after running for a while it seemed to get a bit better - might be my imagination though
It does have a MAF sensor but I haven't done anything with it yet. I disassembled the air intake and cleaned the TB as best as I could (without removing it from the block) and a visual inspection of the MAF. I'm going to take the TB off this weekend and clean that sucker out good as well as at least clean the IAC (or even replace it.)
Thanks for your help and suggestions
Thread Starter
Intermediate
Joined: Jul 2011
Posts: 30
Likes: 0
From: Trondheim, Norway
Find where the computer is mounted on the car, then follow all the wire harness's to see where they end. Once you find the harness with the ALDL on it, post a picture of it and we'll know if it's OBD-1, or OBD-2, and can tell you how to retrieve your codes. Even though it's pieced together, the ALDL is usually put under the dash somewhere under the steering column, for ease of access.
Either way, here are the pics of both left and right sides of the steering column.
Thanks again!