engine dies on the freeway.. while driving

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got a 1990 with a 5.8/e4od and the engine just dies. It started doing it at first whenever I dropped in reverse.. then on occasion when in drive and coming to a stop. NOW it will just cut out fairly regularly whenever the rpms approach idle or when the tranny downshifts to first.. at ANY speed!. THIS is HIGHLY problematic when you're pulling onto an off ramp and suddenly the power steering and brakes cut out or you're approaching stopped traffic and trying to come to a stop while throwing the tranny into neutral and restarting the engine..

the engine will start right back up.. although more recently it has started cutting out right after.

I'm getting a 35 code but I'm not really sure that that is the only problem...

any ideas?

 

[miesk5]

yo

Were both KOEO & KOER tests done? a Self Test by our PAL, BroncoJoe19

do the KOEO = Key On Engine Off portion first

& Remember to have engine @ Normal Operating Temperature before doing the KEY ON ENGINE RUNNING (KOER) portion

If both were not done, try again and post up the Codes here,

DTC 34/336 and 35/337 "...mean that the PFE voltage is too high. This could be the result of a clogged exhaust or the PFE sensor itself; The PFE hose should be examined carefully. We have seen them with pinhole leaks. This causes the exhaust pressure to bleed off giving an inaccurate reading to the PFE sensor. They can also deteriorate because of the corrosive exhaust gases they carry. This weakens the rubber and may cause porosity or cracks. A quick check is to hook a vacuum pump to one side and plug the other side to see if it can hold vacuum...."; read more on testing w/DVOM & vacuum pump

Source: by tomco-inc.com

The PFE/DPFE get hot exhaust altho not much, but hot enuf to eventually fry em.

This shouldn't cause your big problem as you know.

May need to ck out ignition sys esp the Hall Effect; Haynes manual has a simple test when hot.

Overview & Wave Form, Ford Source: by Ryan M (Fireguy50) at fordfuelinjection.com

Shudders, Bogs, & Intermittent No-Spark: Spark w/SPOUT Connector Un-Plugged, but No-Spark w/SPOUT Connected, due to distributor, in a 93 & KOER test won't begin; "...The engine starts to bogg down and then it shudders before it downshifts and smooths out. (example, when rpm’s drop going up an incline it will shudder for a few seconds before the rpm’s increase and it drops out of OD). If I remove the SPOUT the shuddering downshift problems goes away; then, when I replace the SPOUT the shuddering downshift problems comes back; Distributor was causing the problem..." Source: by buck45 at Ford Bronco Zone Forums

ThiS may work; I have not had enuf time to verify all steps and compare each to our Broncos, but it looks right from memory of the Haynes and Chilton tests;

Troubleshooting, Overview & Operation; "...Ford calls this electronic ignition the Thick Film Integrated-IV (TFI-IV) ignition system. The TFI module is also known as the Ignition Control Module (ICM) which reports engine position and rpm to the PCM. The PCM then determines the proper spark timing and advance, and returns a reference signal to tell the TFI module to switch the coil, thereby by creating a spark. The PCM used on these vehicles is referred to by Ford as the Electronic Engine Control-IV (EEC-IV) module..." read more Source: by therangerstation.com

 

[BroncoJoe19]

try cleaning the connectors to the DFE, and checking for vacuum leaks.

I am thinking that if your brakes fail immediately when the engine stalls that you have no reserve vacuum for the power assist.

Tips for Checking for vacuum leaks.

Some of the sensors and some of the actuators either read the amount of vacuum, or use vacuum to move controls, therefore it is important to the proper functioning of the engine that your vacuum system is fully intact. Otherwise one may get codes falsely indicating that there is a problem with a controller/actuator, or a sensor when in reality it is caused by a lack of vacuum.

Look at your rubber vacuum hoses (they are about 1/4 - 3/8 inches in diameter, if they are dry rotted or cracked, replace them. IF they slip on/off of their connectors too easily, they may have stretched out a little bit, cut the ends off, and put them back on.

Courtesy Miesk5 BroncoZone.com. You may listen for a leak. Sometimes using a cut off piece of garden hose is a good aid to listen with. Sometimes a cardboard tube (like from gift wrapping paper) is helpful. Just remember that whenever you stick your head inside a running engine compartment, that you are not wearing any loose clothing or jewelry that can get caught.

Another suggestion is to use a spray can of carb cleaner and spray around the bottom of the intake manifold, and the base of the throttle body assembly. IF there is a leak, you should hear a change in your engine.

Keep a fire extinguisher handy, or use water instead of carb cleaner (it works, but not as well.) Be aware that if you use water and the wires get wet and it runs worse... your wires may be bad, and the water is allowing them to arc instead of jump the gap of the spark plug.

Another suggestion is: to take a propane torch, turn it on (but don't light it) and move it over the vacuum hoses and connections. The engine RPM's will increase if there is a leak and the propane gets sucked in.

Courtesy of TheOldWizard ford-forums... Don't forget to remind folks to check the PCV valve, hose and grommet !

Courtesy Ramnasal ford-forums... Clamp off the hose that runs to the vacuum booster (brake booster) or pull it and plug it. It is possible that the diaphram on the inside of the booster may go bad and cause a vacuum leak.

And one more place that is not always obvious is that the vacuum reserve canister in older vehicles sometimes rots out and leaks, but rarely gets checked. In older vehicles it looks like a metal juice can, in newer vehicles it is made of plastic.

 

[BigBuckingChicken]

I had the same problem of seemingly random stalling. Fix for me was the ignition module. Easy fix and cheap. It bolts onto the side of the distributor. Note that you will need what must be a 5.5 mm allen wrench to do the job or most auto stores should have a specially designed tool for the job. I learned the problem is the module overheats so if this happens more readily on hot days I would give it a shot. Again, easy job, less than $50, and should your module be bad it will give you all kinds of fits.

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