It has been close to a month ago that I took my I6 on a trip out west, but I haven't had any problems with my engine since then. I have some ideas on what happened, but I'll give you guys the whole story and see what you think was the problem.

I had my truck loaded down pretty good (long bed FULL of gear and a trailer with two 4x4 ATVs) and was pushing it pretty hard (70-80 mph on the interstate). Well my old truck was giving the V8 Dodge we were with a run for its money and I must say I was quite proud. As we were passing through MO we hit a traffic jam outside of Joplin, MO due to some road construction. No problem, but after about 15-20 minutes of CREEPING along my tach started jumping erratically (temp. gauge was registering Normal). I started limping for the shoulder and just barely made it! I popped the hood and checked everything (coolant level, fan clutch, belt, distributor cap and rotor, plug wires, computer module [for heat], etc...) After a few minutes I started it back up and it was running like a top again, but a few minutes later it happened again! By this time I was pretty sure it was heat related, but I didn't know how because the engine was not showing any signs of overheating. Well, I popped the hood to let her cool down and we waited until traffic cleared up some before we took off again. The truck ran great after that and only acted up again once we got into the mountains and were crawling over rocks and moguls in the backcountry at about 5-10 mph. Pulled over, let it cool, and everything was okay again! This only happened two times and both times our speeds were around 5mph, otherwise she ran like a CHAMP! On the way back from Colorado I ran her for 26.5 HOURS STRAIGHT without any problems at interstate speeds (the only difference was we never had to slow down)! I have heard in this forum that this engine had a problem at one time with the fuel rail getting too hot, but do you think this was the problem? I keep this engine very well maintained and have NEVER had any complaints with its performance. Any ideas? I plan on upgrading my radiator and changing fans (upgrade to an electrical fan I have my eyes on), but I really don't think this is the actual problem (but it may help). The only symptom was that the truck would start missing and after it was parked you could smell raw fuel (okay, I couldn't because my sniffer is HOSED but my uncle said that he could). Anyway, sorry about the rambling but I am a little puzzled. Please respond. Thanks!

 

Is your 300 fuel injected?

The TFI module is known to overheat and cause problems. It may have something to do with ignition.

good luck, by the way, with your hosed sniffer

 

OH YEAH, good catch rhetor! Yes, it is a '93 (EFI), 4x4, I6, ZF 5-spd (just had to throw that in there because I hate the M@z!@ M5OD!). Anyway, I couldn't feel any excessive heat on any of the electrical/ignition components. Keep the ideas coming!

 

Oh yeah, to all of you kids out there I don't recommend letting your sniffer get hosed because it makes it very dangerous to work around ANY chemicals. Unfortunately the only time I realize I am working too close to chemicals (or someone else using them) is when I develope a splitting headache. Take care of your health and obey ALL safety requirements even if they seem GAY at the time! OOPS, I just fell off of my soapbox (lucky you)!

 

Well it sounds to me like a sensor was malfunctioning, or possibly a loose ground or something annoying like that.

I would try pulling the codes, if you're lucky there'll be a stored trouble code in there. If the problem was that sever it probably threw a code, but hey, never know with these systems.

Good luck!

p.s. I need the warning. I routinely beat the crap out of myself and judgin from the old guys around here (hehe) its a bad idea!

 

The raw fuel he smells bugs me. Check the charcoal canister on the passenger side of the engine compartment. Its possible that your Fuel Pressure regulator is going bad and dumping gas into the canister.

 

The raw fuel smell was only reported during the two little "episodes" my truck was having, and judging from the way that it was running/MISSING I would say that was the cause of the aroma. This problem is definitely heat related (no loose connections, etc... This truck drove over some of the roughest terrain immaginable and never missed a beat).

As far as OLD goes I wouldn't call 27 old! The sad thing is knowing all of the health issues I/the military caused, and the fact that my health will only deteriorate with age. It's scary when I think about that fact.

 

i'm still leaning towards a bad TFI module or bad ignition ground.

Raw fuel smell, missing, that sounds to me like no spark!

 

Yeah, that is what I was thinking at the time but it just didn't feel very hot. The problem was definitely either inconsistent spark or inconsistent fuel delivery, now the problem is deciding which one and what was causing the condition. You sure have been responsive rhetor, but where is everyone else? It seems that usage of these forums has gone down lately. There are some guys that I haven't seen posts from in many weeks. Like whatever happened to steve83? Oh well, keep the ideas coming (I'm all out)! Do these computers have a limp home mode? The engine kept running even though I expected it to die any minute. It could just be due to the fact that these engines are just so tough.

 

yes the computer will default to open loop mode if it detects a problem that it thinks will cause engine damage.

I don't think that open loop mode will neccessarily stutter though, i would think it would simply have a loss of power.

This is one of those hard to diagnose problems because it's so infrequent, you know?

I too am wondering where everyone else is...

 

J.R. is here. I am leaning towards fuel problems since he smelled gas. The charcoal canister is easy to check. There is a vaccum line going to it if I am not mistaken. PUll it off and see if there is fuel in it. I there is then you have a bad fuel pressure regulator.

 

Okay, I will check that but I do not understand how that is related to high engine compartment temperatures. Under normal driving conditions my truck is completely trouble free.

 

BUMP

 

Higher than normal temps can cause some parts to do wierd things. How did the canister check out?

 

No fuel drained out of it when I removed the hose and turned it upright.

Someone has posted on this site before about having a small electric fan that cooled the fuel rail (OEM). Any information on that?