No power
Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
Both of those issues were DTCs. It looks like the only way to check the Cat is to pull it. I will clean the MAF, and really clean the electrical connection as well. Thanks for the response.
Mark
Mark
Pro
Joined: Mar 2020
Posts: 500
Likes: 27
Hello all,
my 85 has 16 DTCs, not sure where to start but low voltage may be a key. I will start cleaning contacts. Any advice on where to start will be very helpful. EST is my starting point. Code 41 is for that. I found my EST connector gone and that wire had a house hold wire nut on it. I crimped a connector there but not an OE connector. This I think could be a big part of the no power issue. Code 51 is a big one as well. I don't want to waste anyone's time putting all 16 here. Thanks in advance for any advice.
my 85 has 16 DTCs, not sure where to start but low voltage may be a key. I will start cleaning contacts. Any advice on where to start will be very helpful. EST is my starting point. Code 41 is for that. I found my EST connector gone and that wire had a house hold wire nut on it. I crimped a connector there but not an OE connector. This I think could be a big part of the no power issue. Code 51 is a big one as well. I don't want to waste anyone's time putting all 16 here. Thanks in advance for any advice.
Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
I bought a Innova scan tool that is OBD1 compatible and gives real time data. Still do not have the center console part fixed. I am going through cleaning every electrical connection I can get to.
Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
DTC Question
Hello all,
After a long time of diagnostic work I have gotten my car from 17 codes down to 6. The six are codes 25, 34, 41, 42, 44, and 51. What I noticed was, all of these codes possibly lead to needing an new ECM. I am going through them one by one with the FSM as my map. Should I just go ahead and replace the ECM. I know this may sound silly but if all of the sensors are good they all lead to an ECM replacement. I look forward to the groups wisdom on this question. Thanks, Mark
After a long time of diagnostic work I have gotten my car from 17 codes down to 6. The six are codes 25, 34, 41, 42, 44, and 51. What I noticed was, all of these codes possibly lead to needing an new ECM. I am going through them one by one with the FSM as my map. Should I just go ahead and replace the ECM. I know this may sound silly but if all of the sensors are good they all lead to an ECM replacement. I look forward to the groups wisdom on this question. Thanks, Mark
Pro
Joined: Mar 2020
Posts: 500
Likes: 27
Hello all,
After a long time of diagnostic work I have gotten my car from 17 codes down to 6. The six are codes 25, 34, 41, 42, 44, and 51. What I noticed was, all of these codes possibly lead to needing an new ECM. I am going through them one by one with the FSM as my map. Should I just go ahead and replace the ECM. I know this may sound silly but if all of the sensors are good they all lead to an ECM replacement. I look forward to the groups wisdom on this question. Thanks, Mark
After a long time of diagnostic work I have gotten my car from 17 codes down to 6. The six are codes 25, 34, 41, 42, 44, and 51. What I noticed was, all of these codes possibly lead to needing an new ECM. I am going through them one by one with the FSM as my map. Should I just go ahead and replace the ECM. I know this may sound silly but if all of the sensors are good they all lead to an ECM replacement. I look forward to the groups wisdom on this question. Thanks, Mark
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Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
Yes, I will get to that, I have six codes, I have time this week. I have gotten 6 codes to go away by cleaning up connectors, the car runs well and is getting good mileage, but when I step on it , no power.
Pro
Joined: Feb 2009
Posts: 655
Likes: 164
From: Vancouver Washington
When you changed the fuel pump did you clean all of the electrical connections there at the pump? Your fuel pressure readings are off to me. I have an 86 and the pressure is 43 with vacuum and 50 without vacuum.
Drifting
Joined: Jun 2018
Posts: 1,402
Likes: 287
From: Brisbane Australia
C4 of Year Finalist (performance mods) 2019
85s run different fuel pressure and different injectors to 86s. They are a one year only deal.
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
Hi
Your fuel pressures are fine the 85 runs lower pressures to later years as your injectors are 24lb, do not trust your harmonic balancer the hub can spin if the rubber bond has broken down. Double check the no1 piston is actually at top dead center, when at tdc on the timing tab.
Check your knock sensor wire is connected and not shorted to the block anywhere, disconnect your battery and reconnect (or the ecm connector near battery) to reset any codes as the ecm can get itself in knots trying to compensate for any perceived problems.
Is usually my first thing to do now as that fixes most of my rough running issues, do not forget your coil it needs spark energy to rev.
The connector at the bottom of the coil through to the rotor button can wear, i have had one cap fail in a big way with the arcing putting a hole there.
Good luck
Your fuel pressures are fine the 85 runs lower pressures to later years as your injectors are 24lb, do not trust your harmonic balancer the hub can spin if the rubber bond has broken down. Double check the no1 piston is actually at top dead center, when at tdc on the timing tab.
Check your knock sensor wire is connected and not shorted to the block anywhere, disconnect your battery and reconnect (or the ecm connector near battery) to reset any codes as the ecm can get itself in knots trying to compensate for any perceived problems.
Is usually my first thing to do now as that fixes most of my rough running issues, do not forget your coil it needs spark energy to rev.
The connector at the bottom of the coil through to the rotor button can wear, i have had one cap fail in a big way with the arcing putting a hole there.
Good luck
Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
Thanks for the guidance. My distributor is all new to include the ignition module and all of the wiring is new. She fires right up, and is getting great milage. No power when you step on the gas. Slow acceleration and the car speeds up nicely and shifts gears. As for the knock sensor, I cleaned all of the connectors and ensured there were no shorts to ground and that code went away. The MAF is the next code to dig into after the MAT. From what I am seeing, I am confident that one of the offending sensors will be identified. I will let you all know how it goes
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
No power can be caused by fuel pressure or retarded ignition, i had a fuel pump that was on the way out and only symptom was the car would not go past 60mph.
as long as you have 4.5vdc with the tps at full throttle ignition on, then if fuel pressure and tps ok the MAF will be the next thing to check.
as long as you have 4.5vdc with the tps at full throttle ignition on, then if fuel pressure and tps ok the MAF will be the next thing to check.
Pro
Joined: Mar 2020
Posts: 500
Likes: 27
I am having trouble finding that model in my searches??
Last edited by Theman5; Aug 7, 2020 at 08:53 AM.
Thread Starter
Instructor
Joined: Dec 2019
Posts: 167
Likes: 10
From: Corpus Christi Texas
I was wrong, the Innova model is a 3120. As for the fuel pump, it is brand new, fuel filter is brand new, and my fuel preasure is within limits. My timing is set to 6°BTDC. I agreed that the MAF is likely. The MAF burn off module is proving to be hard to find for my 85, should that be the issue. The FSM says to check function of that before replacing MAF. This blog has really helped me learn a lot about my vette. I will get to the bottom of it. This weekend I should have time to do more detective work.