Something to look out for bad running truck problem solved

[bruce119]

Well I was having problems with a bad running truck bad idle pore acceleration. Couldn't find the problem changed MAF, FPR, IAC and a few other to try and fix. I have a donor truck so that didn't cost me a fortune.

Any way i read about a LOT of other trucks with similar problems.

I took her to the dealer $$$ I know but I was desperate. I needed a PCM but that wasn't the real problem. The problem was the "Air Hose" that is the molded hose that goes between the MAF and the throttle body. Evidently there was a crack in the seams and went unnoticed undetected by me and other small shops.

So maybe this will mite help someone else who is having problem and can't find the problem. Be sure to check your intake air hose. I would think a good way to test would be to remove seal the 2 large ends and put a vacuum or pressurize using the oil line hook-up.

hope this helps some one.
Thanks to all that helped me I am sure there will be more questions in the future

Thanks
Bruce

 

[Joe Dirt]

Thanks for the update/solution Bruce. A lot of help threads or solutions don't seem to have that final info.

 

[bruce119]

Thanks for the update/solution Bruce. A lot of help threads or solutions don't seem to have that final info.

Yea I am getting to know some of same problems these trucks have. I have 2 '93 explorers now. I had my first for over 10 years and it has close to 250,000 miles.

The Air Hose is something I never even considered and it was probably the source of most if not all of it's problems. The hose is a dealer item and cost $132.29.

 

[KobeJ05]

mine is cracked i put some silicone over the crack

 

[Joe Dirt]

Holy markup!

Gotta love the dealer...

 

[bruce119]

Holy markup!

Gotta love the dealer...

I KNOW I KNOW but I was running out of options. I only wanted a diagnostic I wasn't going to get the work done. But figured in the long run to do it that it would be worth it. The problems fixed once and for all. I have been to small shops they are cheaper but just keep on adding things the trial & error way. And the dealer stands behind there work.

I hope I am done with this problem and maybe help someone else down the road.

 

[YBCold]

yeah the simplest things arent plain to see sometimes. also good idea to check the manifold gaskets and vaccuum hoses. read around the interwebs one site said to get a propane tank with the nozzle an hold it to areas where you think the vacuum leak might be and supposedly that extra fuel will balance the fuel/air mix and make it run better . havent tried this one yet though

 

[Anime]

Mine didn't have a crack, but two of the flexy parts near the MAF end had made contact with the upper coolant hose for a loooong time and melted through. Sure made for a huge air leak, not to mention the amount of unfiltered air that was getting in there.

Sealed it up with silicone and used the plastic hose covers to space the intake tube away from the hoses.

 

[IZwack]

Curious - if this was on an OBD2 vehicle, and theres a crack on the intake tube (original poster's situation), wouldnt that throw a CEL? Considering that the manifold pressure would be off, O2 readings would be off (when compared to the MAF), and so on...

 

[nexis]

Just throwing my 2 cents in, When i suspect a vacuum leak, i bust out my propane torch, (DO NOT USE OXY/acetylene, bad things happen), Turn on the propane with out lighting it, and wave it over vac lines, you will know you are near a leak when the engine picks up some RPMs.

 

[Anime]

91-94's are OBDI. I thought perhaps the intermittent CEL I had was caused by the intake leak, but apparently not. Even after fixing the leak, the CEL is still there, and only throws a code for the TPS.

In my case, the hole was probably always leaking some air, but when it was still pressed against the coolant hose, it likely kept it sealed up just enough, only leaking when bumped over rough stuff.

Not all OBDII systems would throw a CEL for such a thing, there's usually quite a bit of leeway built in regarding airflow, but it all depends on the vehicle.