No start sometimes.

Tiny
J.T.70
  • MEMBER
  • 1989 PONTIAC TRANS AM
  • 5.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 146,200 MILES
When warm engine starts instantly but after sitting overnight it only cranks and won't catch the first time I try. When I shut it off and try again it starts immediately. Tapping accelerator has no effect during first crank. If I prime it with some solvent in the air intake it starts immediately. Garage says fuel pressure is ~46 psi, pump is flowing sufficient volume, injectors are working. It has a new ignition coil. MAF and air filter are clean. The start problem began suddenly after a new starter was installed and the oil changed a few months ago. The engine had to be lifted to squeeze the starter into place.
About the same time it also developed a knock on hard acceleration. I just discovered that the knock is helped with enough fuel additives. These additives also helped raise my MPG from 14 to 19 in one shot. I don't know what the timing is or should be. Everyone says they don't know why the MPG suddenly dropped. It had a similar start problem a few years ago which was also helped by priming it and a new pressure regulator and timing adjustment helped but the new garage says they are okay.
P.S. Battery and starter are good, no lights showing on dash, everything looks and sounds right when I turn it on. Throttle-body is clean. I've sprayed cleaner into throttle-body and put into tank. I'm told the injectors are working. Idle is fine once fuel gets to engine. At times it was sounding loud, throaty and "wet" until it warmed up but after driving a bit with the gas additives the engine idle when cold definitely became quieter and smoother and there was no knock on hard acceleration in addition to restoring my MPG to what it was five years ago, for the duration of that tank of gas. (The quantity of additives required to achieve this is above the recommended amount. I'm on my next tank of gas now and additives are diluted.)
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Monday, June 17th, 2019 AT 5:09 PM

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Tiny
KEN L
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Hello,

This sounds like the knock sensor has gone out. To be sure lets run the codes to see what comes up. here is a guide to help you:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Can you please shoot a quick video with your phone so we can hear the noise? that would be great. You can upload it here with your response.

Please run down this guide and report back.

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Tuesday, June 18th, 2019 AT 7:34 PM
Tiny
J.T.70
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Thanks, I'll get to it ASAP.
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Wednesday, June 19th, 2019 AT 7:31 AM
Tiny
KEN L
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Please let us know what you find. We are interested to see what it is.
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Thursday, June 20th, 2019 AT 11:57 AM
Tiny
J.T.70
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  • 28 POSTS
Hello. The engine codes gave nothing but '12'. The first attached recording is a cold start. The second is a subsequent start after it had warmed a few minutes. I normally don't hear anything when I turn the key to 'on', but with the jumper wire in place the fan would come on when the key was on. The car hadn't been started in about two days so it wasn't warm.
A couple months ago, before I started using the additives, the first start did not start it at all. On the second try there was no cranking before it caught. It was as fast as it usually is, as if it had been primed by the first try even though it didn't sound like any priming was happening because it wouldn't start at all on the first try.
Now that I'm using the additives it sounds more like it wants to start. On this cold start, I held the starter and the engine caught at thirteen seconds. It idled rough and loud gradually smoothing out as it warmed up. I've never needed to hold the starter on for this long. Every time I tried it started better.
I'm on my second tank of gas with anti knock additives. I went from 13.7 MPG 2 months ago to 19.4 MPG this week. That's a normal number.
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Saturday, June 22nd, 2019 AT 5:41 PM
Tiny
KEN L
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Thanks for the videos they really help. This sounds like a weak fuel pump which can be intermittent. To confirm here is a guide to help us test the pressure. Also when it is having a hard time staring can you use starting fluid to make it start?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run down this guide and report back.
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Sunday, June 23rd, 2019 AT 12:36 PM
Tiny
J.T.70
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  • 28 POSTS
Thanks for the instructions, but I don't know anything about working on that system and I don't have the tools to do it. Anyway, there are rules against working on our cars where I live and to top it off I have a bad back.

I agree with you that it sounds like it's not getting enough gas when needed (like a weak fuel pump) but the mechanic measured the pressure a couple times as well as the flow rate and they were fine. I was planning on taking it back to him in a few weeks to recheck the fuel pressure, flow, and pump. All I know is the pump is inside the gas tank and I'm told it could cost close to $1,000.00 to fix. The car is too old to put that much into it considering it will start. I was going to see if he could check the pressure differently so he can look for low pressure specifically during the first cold start attempt. Last time it had this exact problem it was the fuel pressure regulator. I suggested the fuel filter but he didn't think it was the problem. Unless I'm mistaken, it seems that would be the easiest thing to change.

What I don't understand is why the pump continues to pump weakly the first time it is used, but then pumps fine after that. I can see if something was sticking but when it got unstuck it would begin to pump fine. This pump acts badly the whole first time it is used and needs to be shut off and on again to pump better.

To answer your question, the engine will start immediately if I put a small squirt of solvent like acetone in the air intake before I try to cold start it. I'm sure it would also start right up if some was squirted into the intake during the cranking.

Do you have any thoughts about the knock I get on acceleration which suddenly started about the same time as the start problem? Could it be running lean when it needs the extra gas? That would also point to a weak pump or dirty filter not flowing as much as it should, right? The guy says the ignition system and injectors are working and I can't think of anything else.
Thanks.

One more thing. When I turn the key on, but not the starter, should I be hearing the fuel pump start up? I can't hear anything. I've also tried keeping the key in the on position for a few seconds before starting, even turning the key on and off but these actions have no effect on the poor first cold start.
Thanks.
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Monday, June 24th, 2019 AT 4:59 AM
Tiny
KEN L
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It sounds like the fuel pump when you had it replaced did they use an AC Delco unit? If not that is your problem.
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Monday, June 24th, 2019 AT 10:12 AM
Tiny
J.T.70
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  • 28 POSTS
You're right, it turns out the new fuel pump was not Delco. Fortunately it seems to be loosening up or something. Today the engine almost started after 2 sec of cranking. In addition, tapping the accelerator now gets gas to the engine during this first crank to help the engine catch quickly. It definitely was not doing that a few months ago. Much better than 13 seconds & 2 start attempts in the recordings I sent. Maybe I can tap the accelerator before I begin to crank to save starter wear while the gas gets to the engine.
Thanks.
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Friday, June 28th, 2019 AT 3:20 AM
Tiny
KEN L
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Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Saturday, June 29th, 2019 AT 4:35 PM
Tiny
DF_CURT
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  • 3 POSTS
  • 1989 PONTIAC TRANS AM
  • V8
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
Hi. I'm asking this question for a friend of mine who doesn't own a computer.
His 1989 TransAm (305 TBI engine) won't start without a shot of starter fluid. Once it's running it runs fine. He's changed spark plugs, wires and the computer and is now wondering what he can do next. Being it runs we don't feel it's the fuel pump or anything spark related. Any ideas?
Curt
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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Do you hear the fuel pump come on for 2 seconds? If not, check the fuel pump fuse and fuel pump relay, then report back with some testing results.
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
DF_CURT
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He tells me that you can't hear the pump run when you turn the key and there seems to be no fuel spraying into the carbs prior to cranking.
Curt
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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If the fuel pump is not coming On-Check and test the fuel pump fuse and fuel pump relay
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
DF_CURT
  • MEMBER
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OK folks. He got it fixed. Here's the story. My friend took the car to a repair shop. Seems at one point they (the shop) had 3 mechanics working on it. The check fuses, pumps etc for anything that usually causes this kind of problem. But during one attempt one of the mechanics was in the car getting ready for another attempt at starting it. Up to this point they couldn't get the injectors to pulse (the priming squirts that stray during the cranking stage of starting) during cranking. While turning the key the mechanic tilted the steering wheel up (or down) and during the tilting motion the injectors began to work. Seems there was a broken wire within the steering column that connected to the injectors somehow that caused the injectors to work during the starting (cranking) stage of starting the car.
The fix was to replace the key switch and wires running down the steering column. No problems with the car since the repair. Help I explained the repair enough for everyone so that it made sense.
Curt
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
CARIW15
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  • 1 POST
  • 1989 PONTIAC TRANS AM
  • V8
  • 2WD
  • AUTOMATIC
  • 40,000 MILES
My 89 GTA starts some times and other times it won't start like it's starving for gas.
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
HMAC300
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Scan for codes and check fuel pressure with a gauge auto parts rent it. 41-47 psi
https://www.2carpros.com/topics/fuel-system/fuel-pressure-regulator
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Saturday, June 29th, 2019 AT 4:35 PM (Merged)
Tiny
J.T.70
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  • 28 POSTS
Hello Ken,
Things continue to change almost daily. It has gotten easier to start for the last 4 days in a row.
I noticed that I wouldn't hear the fuel pump when I turned the key on the first time, but I was hearing it on every subsequent start, until it sat overnight again. So that is working, just sticking.
For the last 2 days I have heard the fuel pump before starting for the first time. It almost started with 2 sec of cranking. As mentioned earlier, using the accelerator at this point had no effect (was not giving gas to the engine) for the last 2 months, but now tapping the accelerator does help give a squirt of gas to ensure the engine catches. When it does it catches quickly, idles quietly & smoothly without having to warm up first. It sounds better than the second recording I sent.
I've never had the fuel pump shut off for no reason and some people have said if it's bad, it would do that. I now think it's just getting stuck somehow. I also think something else is causing the fuel to flow just slow enough that the engine is getting a bit starved under load.
My top 2 guesses are the fuel pressure regulator (like 3 yrs ago) and the fuel filter.
I think when the garage checked these things the first time they probably had the car outside so needed to start it to bring it inside. This ruined their chances of getting correct initial pressure measurements.
I'm sure I'll see more changes in coming weeks on this same tank of gas.
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Monday, July 1st, 2019 AT 2:01 AM
Tiny
KEN L
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Yep, make sure the fuel pump is an AC Delco also lets clean the throttle bore. Here are two guides:

https://www.2carpros.com/articles/throttle-actuator-service

and

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Please run down these guides and report back.
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Monday, July 1st, 2019 AT 11:21 AM
Tiny
J.T.70
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  • 28 POSTS
Hi Ken. I couldn't do everything you described, but I could see nothing wrong with any hoses, found no leaks. TB & MAF had already been cleaned a few weeks earlier but I did it again.
It's been slowly starting better on its own over time. Then I realized all the symptoms I was seeing could be due to carbonization in the
cylinders & on the plugs so I did a thorough cleaning by spraying different cleaners into the TB of the running engine 3 separate times.

The results were immediate. The next day it had no trouble on it's cold start and it idled smoother. Here are audio recordings and videos of dash from the first start the day after the triple cleaning. Recordings are inside car, windows open, but not in the garage as were previous recordings. The 3 attachments are just sections from the first cold start after cleaning.

#1 Started by itself, no help from me, gets quieter, camera braced on steering wheel-can see the shaking, sounds like a truck. Trouble codes after check engine light came on were 33 & 36.

#2 About 4 minutes. Warming up, smoother. Temp gauge shows it's not yet fully warmed.

#3 About 7 minutes. RPM a little low, usual about 750 stopped & in gear. Smoother, quieter. Pulling back into garage.

Last couple days no starting problems, no preignition under load. I don't understand the initial shaking & loudness in first video. Maybe because this was the first start after cleaning and it's not used to the new conditions yet? Sometimes I've heard the strange "wet" sound again on mild acceleration too. Kind of a gurgling sound, maybe from passenger side. It sounds obvious to me but nobody knows what I mean.
Thanks.
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Sunday, July 21st, 2019 AT 11:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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Thanks for the videos it seems like you have a weak fuel pump let do a pressure test, make sure the gauge up quickly and not slow to pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run down this guide and report back.
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Monday, July 22nd, 2019 AT 10:15 AM

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