I have a 1989 Winnebago Superchief with a Chevy 454, 7.4 liter engine on a P30 chassis. A common problem with the older motorhomes was the Fuel pump relay. Mine is located on the firewall to the right of the gas peddle. I had to do A LOT of research to find a replacement part for my 1989 because it is a discontinued part, but finally found one that works for my Motorhome on an online Winnebago topic thread. The problem causing the malfunction was due to the relay getting too hot causing the relay to stop working properly because the solder would melt on the relay board from the extreme high heat the engine put off. I decided to make a heat shield housing using a small metal electrical wall box I bought from Lowe's insulated it with a high heat fuel injection cover I bought (2) from advance Auto Parts and taped the insulated shield/Box with High temperature Flue tape over my new relay I put on and placed in the same area as the old one against the firewall. I have not had any problem since and the total cost for the new relay & all of the supplies to make the insulated heat shield was $51, and I have extra heat shield tape to use for other projects! I will admit, I researched this relay several weeks and after seeing all of the problems people had with them. I see why Chevrolet decided to change the entire setup starting with I think the 1994 - current models. People were all having the same problem and spent so much money trying to diagnose this issue! If you google my Original Factory GM Relay, you can read for yourself all of the problems.... GM Part # 15528707, The Infamous Fuel Pump Relay! The new relay for my 89 i bought online from Advanced Auto Parts and it is the Wells Vehicle Electronics Accessory Relay Part # 19844. I hope This helps!
I have the same problem. Which relay? There are two side by side, I think the other one is an ignition relay. I could probably figure it out, but you probably already know. Thanks for your help...Ken
My same problem was the injectors. After that was all the sensors that are contacted to the EMC or the "brain". Your weird wire was installed by GM for techs to troubleshoot problems. I bought a Chevrolet service manual that covers Fuel injected gas engines. That should be the thing you should buy. Ebay for $20 + shipping. You will learn a lot about your engine for sure. best $20 I've spent in a while. Now I understand the system and I have mine running again. Good Luck ! Sorry to hear you have to live in Ca.
Fuel pump, yes. Replace fuel filter, fuel pressure regulator. And clean maf, or replace. O2 sensor, too - clean, or replace. Most of this is from age, and/or just sitting.
May want to check the IAC sensor, O2 sensor, map sensor, and the EGR valve. You may also check the TBI gasket for and check the evaporative Emission canister for leaks.
I did fix it, I edited all these videos together, so if you watch the video to the end you will see it run. It was the fuel pump. But now it wont pass smog.
When you're cranking over the engine you gotta leave the throttle all the way closed. Pressing the throttle all the way open will only make the ecu shut off the injectors thinking it's flooded with gas and will just crank without actually gtting any fuel
Check and confirm fuel pressure before anything. Also replace the fuel filter. Mid way between front and rear underneath on inside of frame rail. Judging by the looks of the engine it needs a 'full tune up'...wires, plugs, rotor, cap, ignition coil, pick up coil (remove distributor). Don't use anything other than AC Delco or Delphi.
I just came across your posts. I think you should make a video that shows how you over came the gas consumption issue. I notice you have a TDI carburetor did you end up changing the injectors? Probably you changed the engine temperature sensor? What about the EGR valve? I can't figure out why your fuel pump was a problem. How about the oxygen sensor? Too many sensors, right? Mine is in a k 2500, 1994, 4x4, 8700 gvw. It is a work horse by the gas usage is nuts.
On my 94 GMC I had the same problem and it turned out to be the ICM or Ignition Control Module. Had AutoZone test the old ICM and it tested good on their testing device. You can open the gas tank and listen to see if you can hear it running. Running rich is the temperature sensor on the front of the engine block can be shorted out. Check the wires under the conduit to make sure insulation on wires are good.
check ur fuel pressure regulator and injector poppets inside the throttle body. could be leaky maybe egr and map sensor. these are the common issues on these motors. the coolant temp sensor might be issue but it usually will cause a little miss or power lag cause she would be chokin...i would start with checkin throttle body
I wonder how this would work? Say you get a vintage 1992 454 throttle body and a Chevrolet Performance LSX 454 Long Block Crate Engines 19417357. Would the Throttle Body work on a newer motor like that?
If you look at my other projects you can see I have a lot going on right now, so no not yet. I will wait a few more months for warmer weather before I take another crack at it.
You may have been right about the starting fluid. I ran it for a few days. Took it down the highway. Put fresh gas in her. Then I had it retested, it passed second time around!
I have a 1989 Winnebago Superchief with a Chevy 454, 7.4 liter engine on a P30 chassis. A common problem with the older motorhomes was the Fuel pump relay. Mine is located on the firewall to the right of the gas peddle. I had to do A LOT of research to find a replacement part for my 1989 because it is a discontinued part, but finally found one that works for my Motorhome on an online Winnebago topic thread. The problem causing the malfunction was due to the relay getting too hot causing the relay to stop working properly because the solder would melt on the relay board from the extreme high heat the engine put off.
I decided to make a heat shield housing using a small metal electrical wall box I bought from Lowe's insulated it with a high heat fuel injection cover I bought (2) from advance Auto Parts and taped the insulated shield/Box with High temperature Flue tape over my new relay I put on and placed in the same area as the old one against the firewall. I have not had any problem since and the total cost for the new relay & all of the supplies to make the insulated heat shield was $51, and I have extra heat shield tape to use for other projects! I will admit, I researched this relay several weeks and after seeing all of the problems people had with them. I see why Chevrolet decided to change the entire setup starting with I think the 1994 - current models. People were all having the same problem and spent so much money trying to diagnose this issue! If you google my Original Factory GM Relay, you can read for yourself all of the problems.... GM Part # 15528707, The Infamous Fuel Pump Relay!
The new relay for my 89 i bought online from Advanced Auto Parts and it is the Wells Vehicle Electronics Accessory Relay Part # 19844.
I hope This helps!
I have the same problem. Which relay? There are two side by side, I think the other one is an ignition relay. I could probably figure it out, but you probably already know. Thanks for your help...Ken
My same problem was the injectors. After that was all the sensors that are contacted to the EMC or the "brain". Your weird wire was installed by GM for techs to troubleshoot problems. I bought a Chevrolet service manual that covers Fuel injected gas engines. That should be the thing you should buy. Ebay for $20 + shipping. You will learn a lot about your engine for sure. best $20 I've spent in a while. Now I understand the system and I have mine running again. Good Luck ! Sorry to hear you have to live in Ca.
Fuel pump, yes. Replace fuel filter, fuel pressure regulator. And clean maf, or replace. O2 sensor, too - clean, or replace. Most of this is from age, and/or just sitting.
May want to check the IAC sensor, O2 sensor, map sensor, and the EGR valve. You may also check the TBI gasket for and check the evaporative Emission canister for leaks.
Had the same problem turned out to be the TPS that caused the problem. Mine was a 95 Suburban k2500 7.4 I have a video on it as well on what mine did.
There is a yellow wire that comes from the coolant temp sensor and runs to the ecm.
Running rich it will be the coolant temp sensor.
I did fix it, I edited all these videos together, so if you watch the video to the end you will see it run. It was the fuel pump. But now it wont pass smog.
When you're cranking over the engine you gotta leave the throttle all the way closed. Pressing the throttle all the way open will only make the ecu shut off the injectors thinking it's flooded with gas and will just crank without actually gtting any fuel
It was the fuel pump.
Check and confirm fuel pressure before anything. Also replace the fuel filter. Mid way between front and rear underneath on inside of frame rail. Judging by the looks of the engine it needs a 'full tune up'...wires, plugs, rotor, cap, ignition coil, pick up coil (remove distributor). Don't use anything other than AC Delco or Delphi.
It was the in tank fuel pump. I should do a follow up video. But once I got it running & it passed smog, I sold it.
I just came across your posts. I think you should make a video that shows how you over came the gas consumption issue. I notice you have a TDI carburetor did you end up changing the injectors? Probably you changed the engine temperature sensor? What about the EGR valve? I can't figure out why your fuel pump was a problem. How about the oxygen sensor? Too many sensors, right? Mine is in a k 2500, 1994, 4x4, 8700 gvw. It is a work horse by the gas usage is nuts.
Fuel pump is the problem cause starting fluid is a fuel starving for fuel
On my 94 GMC I had the same problem and it turned out to be the ICM or Ignition Control Module. Had AutoZone test the old ICM and it tested good on their testing device. You can open the gas tank and listen to see if you can hear it running. Running rich is the temperature sensor on the front of the engine block can be shorted out. Check the wires under the conduit to make sure insulation on wires are good.
I fixed it and I sold it.
check ur fuel pressure regulator and injector poppets inside the throttle body. could be leaky maybe egr and map sensor. these are the common issues on these motors. the coolant temp sensor might be issue but it usually will cause a little miss or power lag cause she would be chokin...i would start with checkin throttle body
It was the fuel pump.
I wonder how this would work? Say you get a vintage 1992 454 throttle body and a Chevrolet Performance LSX 454 Long Block Crate Engines 19417357. Would the Throttle Body work on a newer motor like that?
Could be a bad upstream 02 sensor.
throttle body....leaky injectors and fuel pressure reg
did you fix it?
If you look at my other projects you can see I have a lot going on right now, so no not yet. I will wait a few more months for warmer weather before I take another crack at it.
Yes I did finally fix it. It was the fuel pump inside the tank.
temp sensor,fuel press regulator,air pump, check codes o2 sensors ,research and test.
I fixed it, it was the fuel pump.
check the o2 sensor and tps . run gumout fuel cleaner to clean the injectors
also coolant sensor is a big one. if it reads constant cold, the mixture will remain rich. that wire might even be to that sensor
Time it may be off an too must starting fluid
You may have been right about the starting fluid. I ran it for a few days. Took it down the highway. Put fresh gas in her. Then I had it retested, it passed second time around!
Change the oxygen sensor
Hazmat naaaw just put it in the burn pit and burn it
runs like shit
I fixed it, it was the fuel pump.