94 XFI Starts but wont run?

Hi, I have a 94 XFI it starts, idles for about 5 seconds stops and wont start again right away. If I wait a couple hours does the same thing.

I pulled the hose off that runs from the top of the EGR valve to the EGR vacuum module. It starts idles longer but seems weak. When the hose is reconnected dies right away. All the hoses look good with no apparent cracks or deterioration.

I replaced the fuel, fuel regulator, fuel filter still no luck. Checked the codes just 12:confused: . Any ideas appreciated.

First thing to check is to make sure you have fuel pressure and spark.

Almost sounds like a weak fuel pump, but check those things first.

Thanks spark appears good Ill try to get pressure guage

I started on this problem last summer and got pulled away. Just got back to it. After flying all summer got tired of getting felt up by the local TSA guy and having my credit card stolen out of my luggage. So figured Id try to get some fire in the XFI’s pipes and at recent fuel prices it does the job at half the price of a Boeing 737.

Here is what I found hopefully someone can give a second opinion. The XFI runs consistently for 6 seconds then dies. Checked timing belt, spark, and fresh fuel. Good fuel pressure all looks good.

The XFI runs perfect but hisses like crazy with the 3/8” tube from the ERG module to the ERG body removed. Put it back on it dies in seconds.

I removed the tube and let the engine get to operating temperature. Manifold was hot, exhaust pipe before catalytic converter luke warm, catalytic convertor is luke warm, exhaust pipe after Catalytic convertor is cold. I checked the exhaust pressure at the rear very little blowing out the exhaust pipe.

Also the XFI has about 74k on it but originally towed behind a RV so there are fewer miles on engine. It’s always been maintained well. However it’s a single purpose commuter so it’s either driven cross country at high speeds or sets in the garage. When it’s in storage I fire it up to operating temperature every week or two. My guess is the idling carbon plugged up the convertor?

My assumption now is the engine died from lack of O2 rather than the lack of fuel which I originally suspected. When I remove the ERG module tube this provides a minimal venting of exhaust so the engine runs fine without heavy load. Do I have this puppy figured out or did I miss anything else that would cause this condition before the replace the expensive exhaust system?

Unbolt the exhaust system at the manifold where the two big springs are and see if it runs any better.

Man O man thanks, that did it, the XFI runs stronger and smoother than it ever has during the time Ive owned it. Nothing like the rumble of a 1.0L, almost a shame to close it back up. I took the catalytic converter off it looks like it is blocked.

One possible diagnostic that just takes a couple minutes. If you suspect your catalytic converter or you have unexplained odd engine starting, rough idle or weak engine problems with no codes and everything else looks good. If you disconnect the 3/8" tube from the EGR to the EGR module, and the car idles perfect again, gets stronger or stays running it may indicate exhaust blockage likely the converter. I’m a happy camper will have the Geo roadworthy this weekend.

Here is a follow-up for anyone who may need it or if you have more expertise to correct what I don’t understand.

With the catalytic convertor problem behind me it runs and idles absolutely fantastic, and has the power of a thousand chipmunks, it absolutely runs excellent. Man was I happy no more frigen TSA guy feeling me up at the airport.

However I road tested it and under load runs perfect to mid range RPM, then the engine surges slightly and gets weak again, not real weak, the power curve just flattens when it should still have gusto. So to further the art and science of running the interstates at over 50 mpg I applied the EGR port test. As all gods critters ran for cover, I took her up to full power, in the full range of RPM under load and she worked perfect.

If my understanding of the effect of removing the 3/8” EGR tube is correct, this simply bypasses the exhaust system increasing venting volume. My guess is you can tell the efficency of your exhaust system by the volume blowing out of the EGR port. When the catalytic converter was totally plugged removing the tube sounded, like a Boeing product jet wash . With minimal blockage the hiss is noticeably less. To take this one step further, maybe to far? A totally healthy exhaust system/ efficiently running engine, there would be little or no blow by at the EGR port if so it may serve as a quick easy diagnostic. What surprised me is I notice the tube had blown off years ago and had surging at one time. I recall going into a hardware store in Grants New Mexico and getting a clamp for it. I think this converter was deteriorating for years causing decreased power (funny never had a drop in MPG) and odd problems hard to diagnose without knowledge of the EGR Port Test or as the girls call it EPT.

It was cold and I was so glad to find the problem, I over looked what I should have known at the time. I should have known when the ceramic honeycomb just pored out in dust and quarter size chucks it would move down the system. I knew this was a risk as I still remember when the Exxon Valdese was up on blocks at Nasty Co. shipyard I left San Diego opened the throttle and headed cross country and the gas mileage and performance started declining. I disintegrated the converter at high speed in the 1986 Sprint 1.0L and the dust eventually clogged the muffler which took me down just outside of Fruita Colorado. When the weather breaks Ill clear or replace the complete exhaust system so this puppy runs like a champ.