BRONCO 5.8L problem

Do you still have catalytic converters on it? My friends '93 Bronco had a similar problem and it turned out to be bad converters. He had them cut off and now it runs a whole lot better. Erik D. '94 white lightning

Stuck EGR valve could do it, or a vacuum leak. Still could be the catalyst. The core breaks into pieces and can clog the exhaust at higher RPM. Hitting a bump, turning, or braking can re-arrange the broken pieces and let exhaust through again. You usually get a temperature problem while the exhaust is clogged, and the engine pings like crazy. If you crawl under and bang on the cats with your hand or a rubber mallet, you can hear the pieces.

I just banged with the rubber mallet. The only rattles came from all of the heat shielding. I hung onto the heat shielding to damping any resonance and it sounded OK. Also, there was no pinging when climbing up the mountain.

Regarding your other points. Would any diagnostic codes be set if it was the EGR, etc? How about a Fuel Injection coil? It has be 40 years since I screwed around with a vehicle. I consider myself to be a little archaic. Your suggestions are much appreciated.

Thanks,

: > I was just looking at the engine to get inspiration for the problem. It : > looks like there is a coil that could be for the fuel injection on each : > cylinder. Could one of these coils be temperature sensitive?? Maybe the : > shop could have damaged a coil during the tune-up. If so, would a : computer : > code show up?? Maybe I should take it to the Dealer for a diagnostic, : > although I really would like to avoid the dealers. : >

: > Do you or anybody else have a comment? : >

: > Thanks, : >

: >

: > : > New Platinum plugs : > : > New Spark plug wiring : > : > New Distributor cap : > : > New Rotor : > : > Cleaned throttle body : > : > New fuel filter : > : > Ran injector cleaning kit through engine : > : >

: > : > Engine runs beautiful with the following exception. : > : >

: > : > Drove up from San Diego yesterday afternoon to the San Bernardino : > mountains. : > : > About 120 miles. Temperature was about 105F. When ascending Hwy 18 : up : > : > about 5-6% grade with the AC on, the engine began to 'miss' enough to : > cause : > : > shaking. I quickly shut of the AC and it didn't solve the problem. I : > : > pulled off the Hwy and popped the hood leaving the engine running. : > Nothing : > : > seemed out of order. I closed the hood and proceeded up the mountain : > with : > : > the AC off. The Bronco ran strong and good all the way home. : > : >

: > : > I don't have a clue what could cause such a problem. 30 years ago I : > would : > : > have thought Vapor Lock. The temperature gauge was only up about : 50-60% : > on : > : > the scale. There was serious temperature stress, but no overheating. : > : >

: > : > Any ideas? : > : >

: > : : > : : > : Do you still have catalytic converters on it? My friends '93 Bronco had : > : a similar problem and it turned out to be bad converters. He had them : > : cut off and now it runs a whole lot better. : > : Erik D. : > : '94 white lightning : > : : > : : >

: >

: :

I don't know enough about the '92 computer to know if a code would be set for the EGR. My GM of that era only throws a code if the solenoid controlling the EGR valve is kaput, not the valve itself. I doubt it would set one for an injector, unless it caused an overly lean mixture that the O2 sensor picked up.

Something else just came to mind, I hope others will chime in. Ford ignition coils and spark modules tend to cr@p out under heat stress.

Many thanks to all for the suggestions.

The old TFI module predates my model. Aside from just replacing the main coil, is there a way to isolate the problem?

: : Especially if it is the distributor mounted TFI module. Thats something : to look at. Those are very heat sensitive and can cause all kinds of : weird problems. Also, the main coil can cause some weird problems, that : may be worth looking into as well. Good luck! : Erik D. : '94 white lightning :

I have not read through the all the threads so I am sorry if this is redundant. Have you checked the fuel pressure and the fuel filter, on a grade you certainly have more of a fuel demand than on level ground which could explain the occurance as you encountered the hill. A partially clogged fuel injector may cause the same problem. As for the EGR, I think there would have been some pinging as you climbed the hill.

Thanks and good luck.

Joe

----- Original Message ----- From: "Erik D." Newsgroups: alt.trucks.ford Sent: Friday, August 15, 2003 2:44 PM Subject: Re: BRONCO 5.8L problem

I didn't know that. I'll check it out. Thanks.

: > The problem seems to be totally temperature related. Today I was in San : > Bernardino (that's in the valley). It was about 102F down there today. : On : > the way home up the mountain I left the AC off and the Bronco purred like : a : > kitten. I think that discounts a fuel pressure problem. : >

: > I'll probably check around and see if a shop can read diagnostic codes : > without going to a dealer. We're taking off next week to Estes Park, CO : for : > a few days in our 5th wheel. I'll pursue the code thing when we get back. : > I'm leaning toward a coil problem. Either a fuel injection coil or : ignition : > coil that opens with extreme heat. I'm just not sure how to trouble shoot : > such a thing. : >

: > Thanks, : >

: >

: > : > > Something else just came to mind, I hope others will chime in. Ford : > : ignition : > : > > coils and spark modules tend to cr@p out under heat stress. : > : > >

: > : >

: > : > Especially if it is the distributor mounted TFI module. Thats : something : > : > to look at. Those are very heat sensitive and can cause all kinds of : > : > weird problems. Also, the main coil can cause some weird problems, : that : > : > may be worth looking into as well. Good luck! : > : > Erik D. : > : > '94 white lightning : > : >

: > : : > : : > : : >

: >

: :

Sean,

That is a easy and good idea. I'll put in a tank of 93 and put it to the test. I've been using 87. The main coil is easy to change. It would also be worth a try.

Thanks for your comments.

: > The problem seems to be totally temperature related. Today I was in San : > Bernardino (that's in the valley). It was about 102F down there today. : On : > the way home up the mountain I left the AC off and the Bronco purred like : a : > kitten. I think that discounts a fuel pressure problem. : >

: > I'll probably check around and see if a shop can read diagnostic codes : > without going to a dealer. We're taking off next week to Estes Park, CO : for : > a few days in our 5th wheel. I'll pursue the code thing when we get back. : > I'm leaning toward a coil problem. Either a fuel injection coil or : ignition : > coil that opens with extreme heat. I'm just not sure how to trouble shoot : > such a thing. : : One thing about the EFI Ford trucks that I never cared for was that the : spark advance was too aggressive (in my opinion) for low octane fuel in hot : climates. It seems that it in the summer they'll ping like crazy unless you : are using 93 octane, or retard the timing a fair bit. However 93 octane with : 8.5:1 compression is a waste, and retarding the timing will lower the : performance and reduce fuel economy. Still, a tank of high octane is an easy : test to try. : : As for the coil, a hot coil will produce a weaker spark, as will an old : coil. A moderate aftermarket coil helped smooth my truck out when was about : that age. : : Sean : : : :

This one should be a drop-in replacement:

Would a diagnostic code show up if it were the ignition module?

: > I was just looking at the engine to get inspiration for the problem. It : > looks like there is a coil that could be for the fuel injection on each : > cylinder. Could one of these coils be temperature sensitive?? Maybe the : > shop could have damaged a coil during the tune-up. If so, would a computer : > code show up?? Maybe I should take it to the Dealer for a diagnostic, : > although I really would like to avoid the dealers. : >

: > Do you or anybody else have a comment? : >

: : It's must be an ignition module. $50-$80 bucks, easy to change : by yourself. 30min job. My 89 has the module attached to a : distributor. But yours could be a wall mounted. Not sure.

Many thanks for that input.

: >

: : Nope. :