Intermittent starting issues.

[NoSlo]

If it starts when giving some gas pedal, after cranking alone isn't successful for several seconds, I'd consider the idle air controller as a place to start. Instead of replacement, you can take it off, and soak both ports with carb cleaner. A sticky valve will cause the intermittent low idle also reported.

 

[Holiday]

I'll pull the codes again today.

So I pulled the codes. It was a bit confusing this time though.

Discovered that the coolant sensor is not working properly. Looks like the sensor was going bad and possibly previous owner pulled it partially out to hide that fact. I plugged it in proper and a low coolant light came on and sure enough the coolant was quite low. I filled it up but the sensor still reads low coolant. Cleaned contacts but still same light on dash. I also seemed to get a code 321 but that doesn't correspond to anything so I probably read it wrong. I ended up resetting the ECU to see if the coolant light would clear and so I lost previous codes. I guess I'll have to wait/drive for a bit and see what comes up.

 

[Irish Pride]

The sensor in the coolant bottle will not throw any codes and will not effect the drive ability of the car in any way. It's just there to tell you the coolant is low.

Based on your symptoms and past experiences, my guess is a bad PCM. Next time it acts up give the PCM a few love taps with your hand and see if that does anything.

-Chad

 

[Holiday]

Well after changing the cam sensor the car still has intermittent starting issues. Gonna check IAC and PCM next.

 

[luigisho]

Get the Innova code reader. It will save you time and you will need it again

 

[Evan Silletto]

Just a reminder to check and clean all of your major ground points! Back of the intake / firewall by the PCM / passenger strut tower / battery negative to fender well and so many more can cause nearly undiagnosable and intermittent problems… also make sure your battery cables are in good shape. Also the dis must be tight and installed with thermal paste, and I saw a difference after cleaning the mating surfaces of my ignition coil with a wire brush in a dremel as well. People have had weird issues with powder coated intake manifolds, presumably because the dis grounds through the crossover tube to the engine. I had many weird/weak starts and non-starts for a while. After chasing all of these and more down my 89 runs much better. Ymmv

 

[Holiday]

Thanks. Gonna do a full inspect for the ground wires and reseat the DIS. Are all the ground wire connections high on the chassis enough to easily see?

 

[Holiday]

No codes currently. Ground connections are solid, wires to coil and coil connection look clean. Haven't reseated the DIS yet. No codes at all. Seems the car has starting issues randomly after car has ran for a bit, parked for 10 minutes or more and then attempt start again. Once I do get it to start it idles just fine. So it's just this random stumble start, I assume once engine is warm as I haven't had an issue starting the car the next day. Doesn't seem to lack power once driving either. Starter, alternator, battery are relatively new. Plugs I haven't checked and so I'm wondering if it's just a matter of a tune up.

 

[BaySHO Performance]

Might simply be vapor lock in the fuel rails because the engine is still hot. Solution is to give it some gas when trying to restart it.

 

[Holiday]

I keep forgetting to do that. Gonna stick a post-it note on the dash for next time. Thanks.

 

[Holiday]

Might simply be vapor lock in the fuel rails because the engine is still hot. Solution is to give it some gas when trying to restart it.

Also curious...There is what looks like what may be a bleeder valve of sorts for the rails. Has a black nub on it like you see on a simple air valve for tires. Is it meant to bleed the rails?

 

[luigisho]

It's a port to hook up a fuel pressure gauge. Called a schrader valve. Looks like a tire valve.

 

[Holiday]

So, the last time I had a starting issue the car was not hot (sat for over 2 hours). I remembered to try hitting the gas pedal and so I blipped the throttle lightly, not to the floor just a little gas, and the car started.

So it appears that there is an issue with not enough fuel at start. So fuel pump gone bad or perhaps not enough voltage to fuel pump, or fuel pressure regulator issue, or something causing blockage from pump to the fuel rails.

 

[luigisho]

You should confirm with fuel pressure readings. This is assuming the schrader valve still works. You don't want to drop the tank unless you have to.

Yes I would attempt to diagnose the fuel system. Does the fuel pump prime when you turn key to start position before you engage the starter? What is the fuel pressure with pump primed and with car running? If the pump primes the relay module is doing its job.

 

[Holiday]

I'll mention that my car has an ignition lock keypad added by previous owner. So start up is essentially turn key to on position, a momentary humming sound is heard (I assume the fuel pump priming) and then I punch in the code to unlock ignition and then I start the car. So yes I can hear the fuel pump. I'll have to have the fuel pressure checked.

 

[luigisho]

That's the priming. You need to verify the pressure. If the pressure is good pre-start and while running over multiple events then maybe look at injector drivers from the pcm or cam or crank sensor.

However, have you cleared the computer codes and see what pops back up? I wonder if the IAT sensor code is the issue for hard starting and not idling correctly. If this code persists, and replacement of sensor does not fix it, then it is time to look at wiring to the sensor or the PCM.

Also for sh/ts and giggles I would spray the MAF sensor filament with some electronic cleaner.

 

[Holiday]

Going to check codes again but last time I checked there was nothing. It currently idles fine and I don't notice a lack of power when driving. Just the occasional lack of fuel in prime usually after the car has been driven as oppose to having sat overnight.

On a different note I've been noticing a strong burnt smell or something foul from the engine bay or front of the car after driving for 20 min or more. I smell it the second I step out the car. Like burnt plastic or something. My engine temps while driving are in the acceptable range though.

 

[luigisho]

You think maybe coolant or oil dripping & burning on the cats?
If everything is running well...I would check the cam sensor for fouling from oil and yeah I would probably do the fuel pump. Check the tank straps and see how rusted they are. Just get a general idea on the risk of breakage and need for replacement. It doesn't happen often but it is possible. Just be aware that if one breaks that pushes the time to completion way off. Obviously the less gas in the tank the easier life will be trying to drop it with sloshing weight.