1994 with bad drive ablity problem
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1994 with bad drive ablity problem
E 350 with a 5.8 drive ability headache
94 E 350 with a 5.8. about 1/2 throttle or under quick acceleration it bucks violently and will die if you don't let up on the throttle. This all started when it was run out of fuel. I found the condenser wire was shorted to its own body. Causing the PCM fuse to blow. I have since replaced the condenser. Same problem exists. I have replaced the map sensor with a known good one, same with the O2 sensor. The TPS is in range and goes through its range smoothly (this was done on my scanner) Also replaced the fuel pump either due to the fuse blowing or running it out of fuel it wasn't working. Fuel pressure is 30 to 32 psi. I've checked the EGR for leaks and proper operation. I have noticed its very hard to start when its cold. Someone has had problems with it in the past as cat is new and i have noticed some things have been removed or replaced recently. The van was just purchased a few weeks ago by my buddy. Any ideas or help would be greatly appreciated.
I know this isn't in the right forum, but i hoped i would get more answers/help here. thanks. and yes the cat has been replaced.
94 E 350 with a 5.8. about 1/2 throttle or under quick acceleration it bucks violently and will die if you don't let up on the throttle. This all started when it was run out of fuel. I found the condenser wire was shorted to its own body. Causing the PCM fuse to blow. I have since replaced the condenser. Same problem exists. I have replaced the map sensor with a known good one, same with the O2 sensor. The TPS is in range and goes through its range smoothly (this was done on my scanner) Also replaced the fuel pump either due to the fuse blowing or running it out of fuel it wasn't working. Fuel pressure is 30 to 32 psi. I've checked the EGR for leaks and proper operation. I have noticed its very hard to start when its cold. Someone has had problems with it in the past as cat is new and i have noticed some things have been removed or replaced recently. The van was just purchased a few weeks ago by my buddy. Any ideas or help would be greatly appreciated.
I know this isn't in the right forum, but i hoped i would get more answers/help here. thanks. and yes the cat has been replaced.
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Joined: Sep 2006
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It is noble of you to try helping a friend as second party with an operating system that is totally different than the 97 up systems by trying it in this 97-03 forum.
The year 94 runs a speed density EEC system.
Does your scanner work on that system? If yes what 3 digit codes are present?
What happens to the fuel pressure during operation?
Has the ignition system been checked out?
The TFI, the cap/rotor, plug wires, timing etc.
Hard starting is a clue that involves fuel pressure, cylinder head temperature sensor and intake air sensor and the ignition switch.
Need in depth troubleshooting to fix up a truck that was in unknown condition before purchase.
Good luck.
The year 94 runs a speed density EEC system.
Does your scanner work on that system? If yes what 3 digit codes are present?
What happens to the fuel pressure during operation?
Has the ignition system been checked out?
The TFI, the cap/rotor, plug wires, timing etc.
Hard starting is a clue that involves fuel pressure, cylinder head temperature sensor and intake air sensor and the ignition switch.
Need in depth troubleshooting to fix up a truck that was in unknown condition before purchase.
Good luck.
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94 drive ability problem
fuel pump is new 30 to 32 psi. tfi has been checked at parts store, ran the test 5 times
had a tune up shortly before it was purchased. It's obvious to me he bought someone else problem with what has been tried so far. It's very hard to start cold, but the running problem seems to get worse the warmer the engine is
had a tune up shortly before it was purchased. It's obvious to me he bought someone else problem with what has been tried so far. It's very hard to start cold, but the running problem seems to get worse the warmer the engine is
Lead Driver
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On fuel pressure it depends on how it was tested.
Vacuum on the regulator or off.
The pressure should be in the 35 to 38 range assuming the gauge is accurate.
Here is how the cold start works.
At key on the EEC looks at the values of the coolant sensor, and the intake air sensor to set the fuel, open the IAC to raise the idle and advance the ignition timing.
If any one of these actions fail the cold start and drive off will be impaired.
The OX sensors are not involved until about 1 minute or more after cold start or until they heat to a temperature of 600 degrees.
After this point the Ox sensors take over fuel control and depend on the fuel pressure to be high enough not to run the motor lean.
.
The Map sensor also depends on fuel pressure to add more fuel as the intake vacuum goes down.
Vacuum on the regulator or off.
The pressure should be in the 35 to 38 range assuming the gauge is accurate.
Here is how the cold start works.
At key on the EEC looks at the values of the coolant sensor, and the intake air sensor to set the fuel, open the IAC to raise the idle and advance the ignition timing.
If any one of these actions fail the cold start and drive off will be impaired.
The OX sensors are not involved until about 1 minute or more after cold start or until they heat to a temperature of 600 degrees.
After this point the Ox sensors take over fuel control and depend on the fuel pressure to be high enough not to run the motor lean.
.
The Map sensor also depends on fuel pressure to add more fuel as the intake vacuum goes down.
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headache continues
I have since checked the fuel pressure while running and making the van fall out. The pressure is good at the time it goes flat and stumbles. i did find that the coolant temp and intake air temp both read about 10 degrees lower that the actual air temp at cold start up. Also the last time it quit /stumbled on me it was so violent that the engine dieseled and ran backward throwing the belt. After re installing the belt i went to start the engine and found i had nothing. It wouldn't crank and the warning lights on the dash didn't even come on. Neither did the fuel pump pressure up. after turning the key off and on several times it finally came back to power and would start and run. As far as checking the fuel pressure i did it with the hose on and off. i also tried applying different levels of vacuum to the regulator to see if it made any difference. all the same.
Lead Driver
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With fuel eliminated as a possibility it leaves ignition.
The dieseling tells me the ignition timing is to far advanced for some reason.
The results is hot spots in the combustion chambers that act to fire the remaining fuel that might be available and or there could be feedback voltage to the system. Normally a relay drops when the key is off preventing voltage to the system but a remaining charge could fire things a short time.
There are two sources for this.
1. The base timing has been set to far ahead.
To check and set this, the SPOUT plug has to be removed then the base timing looked at with a timing light and adjust the distributer position to align the 10 degree marks on the crank pulley and the pointer tab.
Then re install the SPOUT plug.
2. If EGR is leaking or open the timing will go advanced as well as the motor running poorly.
Check these items out next.
Good luck.
The dieseling tells me the ignition timing is to far advanced for some reason.
The results is hot spots in the combustion chambers that act to fire the remaining fuel that might be available and or there could be feedback voltage to the system. Normally a relay drops when the key is off preventing voltage to the system but a remaining charge could fire things a short time.
There are two sources for this.
1. The base timing has been set to far ahead.
To check and set this, the SPOUT plug has to be removed then the base timing looked at with a timing light and adjust the distributer position to align the 10 degree marks on the crank pulley and the pointer tab.
Then re install the SPOUT plug.
2. If EGR is leaking or open the timing will go advanced as well as the motor running poorly.
Check these items out next.
Good luck.
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i unplugged the egr and it made no difference. I didn't take it off as its a bugger to get to. Is showing about 21 to 24 degrees advance at the 2100 to 2200 rpm where the engine bucks and then lays down this think is just like you turned off the key at the rpm i mentioned. But if you let up it will come back and run. If you don't it backfires and will stall out or diesel and do all kinds of crazy stuff. It backfired on the owner the night it first started this and has split the exhaust at the header pipe/crossover pipe. The EGR appears to be full electric only no vacuum
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