Trouble Shooters- Please Read
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Trouble Shooters- Please Read
It all started about 700 miles ago. First there was Hesitation @ WOT. Then it got progessively worse from there. Now car turns over but shuts off emmedietly.
Here is what I have done so far.....
New fuel filter
New O2 sensor
Two new MAF relays.
Car was tripping codes 33, 34, and 44 however not at the same time. Just before car was un-able to stay running,(shutting off emmedietly) hesitation/stumbling was so bad that I had to keep one foot on the gas and one on the brake to keep the car from stalling.
This afternoon i pulled all of the plugs and did notice some small deposits of oil on some of them. How much oil found on the plugs would warrant concern?
Thanks in advance,
Chuck
Here is what I have done so far.....
New fuel filter
New O2 sensor
Two new MAF relays.
Car was tripping codes 33, 34, and 44 however not at the same time. Just before car was un-able to stay running,(shutting off emmedietly) hesitation/stumbling was so bad that I had to keep one foot on the gas and one on the brake to keep the car from stalling.
This afternoon i pulled all of the plugs and did notice some small deposits of oil on some of them. How much oil found on the plugs would warrant concern?
Thanks in advance,
Chuck
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: Trouble Shooters- Please Read (chucks88)
ick. sure its oil?
could be head gaskets... not uncommon.
you could also be dealing with a huge vacuum leak. Check your intake manifold. That would explain the oil, too. if the intake gaskets are that bad, the engine will suck in oil from the galley...
I would also check the Throttle Position Sensor.
I think these problems are also systematic of a bad ECU... but I don't remember for sure.
could be head gaskets... not uncommon.
you could also be dealing with a huge vacuum leak. Check your intake manifold. That would explain the oil, too. if the intake gaskets are that bad, the engine will suck in oil from the galley...
I would also check the Throttle Position Sensor.
I think these problems are also systematic of a bad ECU... but I don't remember for sure.
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Trouble Shooters- Please Read (chucks88)
If your description is accurate...It's definitely sounding like TPS.
How about giving a few more clues, like was there a certain speed it was smooth at? Was there any exhaust system rattles? Etc...
How about giving a few more clues, like was there a certain speed it was smooth at? Was there any exhaust system rattles? Etc...
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Re: Trouble Shooters- Please Read (bogus)
It sure smells like slightly burnt oil. What other liquid COULD it be? Antifreeze possibly.
Also just noticed that when i shut the car down, there is a depressurizing like sound that appears to be coming from the passenger side on the side of the block.
It is somewhat smooth if i keep the car at one rpm, either highway, street Etc. But if I were to attempt to floor it it would bog down/out
[Modified by chucks88, 6:05 PM 4/11/2002]
Also just noticed that when i shut the car down, there is a depressurizing like sound that appears to be coming from the passenger side on the side of the block.
It is somewhat smooth if i keep the car at one rpm, either highway, street Etc. But if I were to attempt to floor it it would bog down/out
[Modified by chucks88, 6:05 PM 4/11/2002]
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Trouble Shooters- Please Read (chucks88)
You may have several problems: i.e. MAF & fuel pump.
Put a FP gauge on the Schraeder valve on the fuel rail and turn On the ignition key. The fuel pump should run for 1.5-2 sec and the fuel rail will pressurise to about 40-45psi. If not check the FP fuse and FP relay.
If OK, pull the FP, open the small black connector just under the mounting flange and clean the three brass contacts (they become oxidized over time).
If you can get it started, pull the connector to the MAF; if idle improves service the MAF or it's relays.
You can test the TPS by opening it's connector and monitor a DMM as you slowly move the throttel from closed to full open. The resistance readings should increase smoothly with no jitter, skips or flat spots.
Once it's running again, jumper ALDL pins A&B and turn On the ignition. After about 1minute, disconnect the IAC. Then start the engine, set the idle to about 450rpm and measure the TPS value. Set it to 540-650mV.
If you had MAF problems it could have caused the code 44 too.
You need to address the problems systematically, get it running again is the first issue. If you know someone with a scan tool, enlist their assistance.
Put a FP gauge on the Schraeder valve on the fuel rail and turn On the ignition key. The fuel pump should run for 1.5-2 sec and the fuel rail will pressurise to about 40-45psi. If not check the FP fuse and FP relay.
If OK, pull the FP, open the small black connector just under the mounting flange and clean the three brass contacts (they become oxidized over time).
If you can get it started, pull the connector to the MAF; if idle improves service the MAF or it's relays.
You can test the TPS by opening it's connector and monitor a DMM as you slowly move the throttel from closed to full open. The resistance readings should increase smoothly with no jitter, skips or flat spots.
Once it's running again, jumper ALDL pins A&B and turn On the ignition. After about 1minute, disconnect the IAC. Then start the engine, set the idle to about 450rpm and measure the TPS value. Set it to 540-650mV.
If you had MAF problems it could have caused the code 44 too.
You need to address the problems systematically, get it running again is the first issue. If you know someone with a scan tool, enlist their assistance.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Re: Trouble Shooters- Please Read (88-406)
I picked up a volt meter tonight. Never used one before. I will be testing both the MAF and TPS. I post my results on this thread.
Chuck
Chuck
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Re: Trouble Shooters- Please Read (jimbos86vette)
My vote is on fuel pressure!
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Trouble Shooters- Please Read (chucks88)
Smooth at one rpm but erratic at changing throttle position points to the TPS.
Definitely check the TPS.
A MAF problem, on the other hand, will make the car not idle unless you unplug the MAF connector. A Cat converter problem would rattle or cause the engine to loose power at anything ( including steady rpm power loss ) ABOVE idle, but generally will not effect idle.
The oil smell could simply be an oil leak, common out of the rear of the intake manifold/lifter valley seal or it could even be trans fluid dripping off the driveshaft yoke seal and falling on the hot catalytic converter.
The hissing sound can be as simple as AC fluid bleeding down or even coolant cycling into the recovery tank. I would not worry about it unless you overheat.
[Modified by BBA, 11:28 PM 4/11/2002]
Definitely check the TPS.
A MAF problem, on the other hand, will make the car not idle unless you unplug the MAF connector. A Cat converter problem would rattle or cause the engine to loose power at anything ( including steady rpm power loss ) ABOVE idle, but generally will not effect idle.
The oil smell could simply be an oil leak, common out of the rear of the intake manifold/lifter valley seal or it could even be trans fluid dripping off the driveshaft yoke seal and falling on the hot catalytic converter.
The hissing sound can be as simple as AC fluid bleeding down or even coolant cycling into the recovery tank. I would not worry about it unless you overheat.
[Modified by BBA, 11:28 PM 4/11/2002]
Pro
Joined: Dec 2000
Posts: 700
Likes: 20
From: Derby Kansas
Re: Trouble Shooters- Please Read (chucks88)
Just before car was un-able to stay running,(shutting off emmedietly) hesitation/stumbling was so bad that I had to keep one foot on the gas and one on the brake to keep the car from stalling.
I had the EXACT same problem as above when I had my 92 Z28. I didn't have any codes or top-end stumble though. It ended up being my ignition module. The car only had about 60,000 miles on it at the time. Just another possibility to consider.
I had the EXACT same problem as above when I had my 92 Z28. I didn't have any codes or top-end stumble though. It ended up being my ignition module. The car only had about 60,000 miles on it at the time. Just another possibility to consider.
Thread Starter
Safety Car
Joined: Oct 2001
Posts: 4,763
Likes: 1
From: Connectivette
Re: Trouble Shooters- Please Read (Ron78Z&85Vette)
Problem solved, learning experience gained. Tps voltage tested @ .53 So I started to look elsewhere.
I re-read the instructions for testing the MAF sensor and said to myself "you dumb ***" When it said to disconnect the MAF sensor to see if it runs better with out it, I took the whole f'in thing out and it still ran like crap. This time I just left it in place and just diconnected the connector and it runs just fine.
I re-read the instructions for testing the MAF sensor and said to myself "you dumb ***" When it said to disconnect the MAF sensor to see if it runs better with out it, I took the whole f'in thing out and it still ran like crap. This time I just left it in place and just diconnected the connector and it runs just fine.