Adjustment after intake gaskets changed
Thread Starter
Instructor
Joined: May 2006
Posts: 182
Likes: 1
From: Metairie Louisiana
Adjustment after intake gaskets changed
Just had the intake manifold gaskets changed on my 87 coupe. Went to pick it up and arrived just as it was completed. I started the car and it would kill when placed in gear. My friend (a mechanic) repositioned the TPS and it seemed to idle better, but I noticed my voltage is not as strong as what it used to be. Also, the car seems to have lost power. I'm thinking the timing could be off since the distributor was removed/replaced to do the work. I left the car so that adjustments could be made and hoping that will solve the problems. Anyone else had similar problems?
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
The tps is set with a voltmeter. If he simply loosened it and twisted it, shame on him. Set the tps properly, put a timing light on it to verify timing. 6 degrees before tdc is the factory spec. If voltage is down, check the connections at the alternator. They may simply be loose.
Cruising
Joined: Dec 2004
Posts: 13
Likes: 0
Same intake problem here...
I have similar issues with my 88. Changed the intake Myself, thought I did a great job and now I have less power, failed emissions and when cold feels like a carbed car without a choke. Ive checked every vac hose, elec connection, TPS adj, fuel pres, vac pres and more. But I still have a hesitation. I did change the EGR valve and fuel injectors. Im about ready to send it to the dealer but money is tight. anybody else have anymore suggestions?
Cruising
Joined: Dec 2004
Posts: 13
Likes: 0
Bosch injectors
I purchaced 22 lb Bosch/Ford Design II 0280150561 FOTE-D9B fuel injectors. They came from a vendor on Ebay who claimed they fit and were equivelent to the stock injectors. I took a chance becuase he does have a 1 year money back no matter what. The only trouble is that I could not find any info on these. But If you think its the injectors what could be done inorder to keep them?
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
Lee: I do not know you level of skill on working on engines. However, I would suggest the following:
1. Check the reisitance of the injectors. All 8 injectors should be very close to the same reading. These are Bosch style and are usually reliable.
2. Examine each vac line and make sure it is correctly routed to its proper position and tight on the fitting.
3. Make sure all bolts on the intake and other removed parts are tight as they should be.
4. Check the timing of the engine to make sure it is set properly.
5. Do a base idle check to assure the TPS is properly set.
Changing out the intake manifold gaskets requires many parts to be disconnected and reconnected. In addtion, there are areas that must be sealed properly for the car to run correctly. I would guess that something has not been reinstalled correctly ...... assuming you have good injectors.
Here is a contact for injector questions as I am not an expert on this: Rich Jensen at Cruzin Performance is very good and is a straight shooter. His email address is: rich@cruzinperformance.com
Good luck and let us know how this turns out!
1. Check the reisitance of the injectors. All 8 injectors should be very close to the same reading. These are Bosch style and are usually reliable.
2. Examine each vac line and make sure it is correctly routed to its proper position and tight on the fitting.
3. Make sure all bolts on the intake and other removed parts are tight as they should be.
4. Check the timing of the engine to make sure it is set properly.
5. Do a base idle check to assure the TPS is properly set.
Changing out the intake manifold gaskets requires many parts to be disconnected and reconnected. In addtion, there are areas that must be sealed properly for the car to run correctly. I would guess that something has not been reinstalled correctly ...... assuming you have good injectors.
Here is a contact for injector questions as I am not an expert on this: Rich Jensen at Cruzin Performance is very good and is a straight shooter. His email address is: rich@cruzinperformance.com
Good luck and let us know how this turns out!
Last edited by Sam Lam; Aug 9, 2006 at 10:53 AM.
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
Hey Lee,
I used this forum suggested technique with great success to find a vacuum leak I have in my intake system, and I think it is worth the time for you to check yours.
1)Find a person who smokes.
2)Remove the snorkle going to the throttle body
3)Insert a 3-4' piece of tubing into the throttle body and let the plates close on it (make sure it is stiff enough to not be crushed).
4) Seal up the entrance to the throttle body (a towel was suggested, but I found that pieces of wide masking tape worked much better).
5)Have the smoker exhale into the tube. It will take a while to fill up the entire TPI system, so expect this to take a few minutes.
6)Once the intake is full of smoke, every additional exhale will push smoke out of any vacuum leak.
HTH!
I used this forum suggested technique with great success to find a vacuum leak I have in my intake system, and I think it is worth the time for you to check yours.
1)Find a person who smokes.
2)Remove the snorkle going to the throttle body
3)Insert a 3-4' piece of tubing into the throttle body and let the plates close on it (make sure it is stiff enough to not be crushed).
4) Seal up the entrance to the throttle body (a towel was suggested, but I found that pieces of wide masking tape worked much better).
5)Have the smoker exhale into the tube. It will take a while to fill up the entire TPI system, so expect this to take a few minutes.
6)Once the intake is full of smoke, every additional exhale will push smoke out of any vacuum leak.
HTH!
Cruising
Joined: Dec 2004
Posts: 13
Likes: 0
Thanks Guys
Unfortunatly the smoke test revealed only that the throttle body shaft has a slight leak and the top rubber seal on the passanger side valve cover has a slight leak. Both of these were already there. If I had a leak it should have shown itself due to the fact that I used a porta power air pump and rigged two plastic cups togeather and used 4 cigerettes to force the smoke, under presure, into the hole engine. So heres another question, if I have an internal intake gasket to head leak, how do you diagnose that?
Unfortunatly the smoke test revealed only that the throttle body shaft has a slight leak and the top rubber seal on the passanger side valve cover has a slight leak. Both of these were already there. If I had a leak it should have shown itself due to the fact that I used a porta power air pump and rigged two plastic cups togeather and used 4 cigerettes to force the smoke, under presure, into the hole engine. So heres another question, if I have an internal intake gasket to head leak, how do you diagnose that?
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Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
Smoke test....
Lee: Find someone with a scanner and see what is going on with your engine sensors. This will lead you to the problem. Otherwise, you will just be throwing $$$ and time into the car and you may not luck up and find the problem.
Lee: Find someone with a scanner and see what is going on with your engine sensors. This will lead you to the problem. Otherwise, you will just be throwing $$$ and time into the car and you may not luck up and find the problem.