Runs like crap and can't start when it warms up

[mazdags94]

^^^^^^^ wow, that is really tough to read

[onlytrueromeo]

I think this is someone on the forums trying to be funny, except that they're failing epically!

[Leedeth]

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Please, do go on.

[Mad Cow]

See the newest post for the latest info

[coltfoet5]

I have a similar problem that I saw nighhawk refer to in this thread. When I Leave it outside in the cold for a long period it won't start. If I push it into a garage about 2 hours later it will start fine. Does anyone know the problem and how I can fix this?

[nightfire]

Good luck man... this seems to be a tough one. You'll get it figured out!

[nightfire]

I have a similar problem that I saw nighhawk refer to in this thread. When I Leave it outside in the cold for a long period it won't start. If I push it into a garage about 2 hours later it will start fine. Does anyone know the problem and how I can fix this?

When you've got your engine idling normally (~700-800), turn on a heavy electrical load (ie. rear defrost, blower motor). Do the RPMs drop, or rise?

If they drop, it's probably a stuck IAC. It's not closing the intake during cold starting, and because cold air is more dense, it could be running too lean to light up, then too rich on the next stroke.

If the RPM rises, your IAC is working properly so it's something else. In my case I know I had all sorts of vacuum leaks at the time, and a gunked up VAF. Bad compression or bad disty I'd suspect first.. :/

When you push it into the garage, do you pull the plugs to let it air out, or just let it warm up?

I'd strongly recommend ordering a USB OBD-II reader off ebay. They're like $20-30 shipped, and make life so much easier. You can read the codes, as well as monitor things like intake air temp and coolant temp. A bad coolant temp sensor can also cause trouble (because it's the ECUs primary engine temp source), and something like that would show up in the sensor log.

[Mad Cow]

Ok, so I installed an external coil, started up perfectly, ran beautifully... until it warmed up. It got up to operating temperature (the IM got pretty warm) and it just died. Tried starting it again and it didn't flood, just kept turning. I pulled out the fuel injector fuse, cranked it for a bit, put the fuse back in and it just barely started, it ran pretty badly, it stuttered a bit at any RPM below 4k and died when I brought it back to idle. Did the fuel injector fuse thing again and it cranked for a while trying to catch and finally started again (I was cranking it and playing with the throttle so it's not an idle-related problem). I did this a few times, pulled the plugs and they were black as soot, and there was black crap all over the ground near the muffler and it was spitting white smoke out the exhaust. It then gave me a bunch of random CEL codes.

The weird thing was, the temperature gauge goes down to the bottom when the engine runs, then went to the middle when it died. The wiring harness is crap, there are broken connectors, broken wire shielding, cut wires and random wires all over the place. So what could it be? Bad coolant temp sensor? Bad wiring harness? I'm near the end of my rope here, everything I've tried has only made it slightly better.

[SmoothMX3]

Umm... I'm no smart guy or anything, but...
Wouldn't it be smart to fix anything on that harness?
If you have split's in your wires or anything like that, what would it hurt to just fix all that and eliminate small problems? - Fix your harness, then drop a few more lines.

[Mad Cow]

I didn't want to get into the harness until it warms up, but I guess I have no choice. I have 2 partial harnesses coming in the mail so I'll pull mine today and combine and fix them.

[nightfire]

Yeah.. if it ran well, then randomly and suddenly died, it definitely sounds like an electrical problem. Carbon deposits on plugs usually indicates a very rich burn, but at this point it could be the signal (or the device itself) to/from the VAF, the TPS, or even the fuel injectors. I'd definitely try a new harness next.

[Mad Cow]

I just pulled the harness, finding even more torn wires, unconnected plugs and random splices along the way. But it's not random or sudden, it just generally runs like crap, can't idle, and can barely start when it's warm, only when it's warm.

Well this is gonna be fun, putting together a wiring harness.

[Flyer]

I just pulled the harness, finding even more torn wires, unconnected plugs and random splices along the way. But it's not random or sudden, it just generally runs like crap, can't idle, and can barely start when it's warm, only when it's warm.

Well this is gonna be fun, putting together a wiring harness.

Take good notes, since I may need it to fix my harness >_>

[Mad Cow]

I think I need to replace both coolant temp sensors, so have some questions. First off, which one is the one that controls the fan and which one goes to the cluster? (I have the older style 2 sensors harness and ECU). Are they both the same resistance-wise? And finally, how do you get them out, a really long socket? And what size socket?