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Post by JustyRally on Jan 8, 2013 14:07:22 GMT -5
1990 MPFI 5 speed 4x4 Runs cold with power - no power after it's warm but still runs. I can put my foot to the floor and it still runs just no power? Im guessing it's running in choke mode with power and when warm it switches off reads the sensors and acts like this. Does anyone know off hand what sensor would cause this? Seems like it may have something to do with the pressure sensor switch. Does anyone have the know how to test it. I really need to buy a service manual. Any help and ideas would be greatly appreciated.
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Post by Armageddous on Jan 8, 2013 23:11:26 GMT -5
Is your check engine light on? If so you should get the codes. If it's not on I would go after your fuel supply/filter.
Terry
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Post by JustyRally on Jan 9, 2013 4:09:30 GMT -5
No check engine light. The fuel filter is new....If it had a fuel problem i think it would of died when i a put the pedal to the floor?? It just stays running, if i feather it just right the RPM will go up and climb in neutral.
I all ready adjusted the TPS I gutted the catalytic converter thinking it may be clogged.
Just seems to have the problem when it gets warmed up. I may go ahead and get a new fuel pump just for the hell of it.
Any more help and ideas would be greatly appreciated.
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Post by JustyRally on Jan 9, 2013 12:35:08 GMT -5
I rethought what you said, when the fuel pump gets warm it may be locking up/slowing down. Still strange the it stays running with my foot to the floor and without RPM increase.
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Post by blacklight on Jan 9, 2013 18:03:22 GMT -5
My bets are a seized bearing in the pump that limits the pumps ability to spin.
Have you measured the fuel pump relay, so that it gets enough power?
//Magnus.
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Post by JustyRally on Jan 10, 2013 3:51:28 GMT -5
It seems like if it was a fuel problem and i put my foot to the floor it would lean out and die....but it stays running
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Post by JustyRally on Jan 28, 2013 14:03:54 GMT -5
I put a new fuel pump in and it did NOT fix the problem. Is there anything temperature related that my cause this...temp sensor? Im just racking my brain on this one?? New things observed: Under the oil filler cap is lung butter...It wasnever like this before...PVC valve not working, it seems to be just sliding back and forth no spring action. After it got real warmed up siting still it had a hard time starting again, after cool started right up. Is it possible the thermostat is stuck shut and the engine is over heating....Maybe the water pump is not moving water. Im not getting any strange smoke from the exhaust...just smells like gas exhaust. In general im thinking the PVC valve is bad I did have a erratic high idle problem before this strange behavior. subarujusty.proboards.com/index.cgi?board=engine&action=display&thread=4668Im getting a new PVC valve. Any other input would be great.
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Post by 88gl on Feb 6, 2013 18:41:46 GMT -5
Did the PVC valve fix it?
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Post by JustyRally on Feb 7, 2013 14:24:46 GMT -5
The PVC did not fix my problem but seems to idle better.
Well the gunk under the oil cap got worse and im definitely getting coolant in my oil....and i observed some coolant driping from/around the water pump area.
I took the radiator cap off filled it up when cold, let it warm up i only seem to have flow when i rev it up. The coolant turned from clear to cloudy maybe very small bubbles when i reved it. It was plenty warm/hot fan kicked on for a second....radiator not very hot.
Im not sure if I have a blown head gasket, or the water pump is bad and the pressure is pushing coolant past the seal into my oil. Im thinking it's over heating. Not sure how much flow i should see when it's just idleing.
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Post by Armageddous on Feb 7, 2013 23:49:42 GMT -5
So the problem is exactly the same? Runs fine cold and lacks power when warm? Strange for an EFI car..
Sorry to mislead on the fuel pump.
Are you sure you're getting coolant in the oil? If you have a foamy white sludge on the inside of your oil cap, that does not mean you have coolant coming in to the oil. If you check the oil with the dipstick and it looks white and foamy, then you do. If it is only under the cap it is likely just condensation, usually from short drives in cold weather.
If you have a leak near your water pump try to determine where it's coming from. There is a weep hole in the crankcase cover and if it's leaking out of there then your mechanical seal is faulty. If it's leaking behind the crankcase cover, you need to yank that cover off before it destroys your engine.
As far as the running issue the only thing that comes to mind is possibly a bad MAP sensor, but that's a long shot. Does your check engine light come on? I s'pose it could be the valve adjustment too, they could be getting super tight when warm and not letting the valves close.
If you could describe the running issue in really good detail I may be able to help more.
Terry
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Post by RedRooJusty on Feb 9, 2013 15:34:48 GMT -5
**JustyRally**, what you are describing sir is a timing issue.
Your engine's MPEFI ECU will provide a choke like function when cold, by enriching the AFR and adjusting the timing.
About the timing.. As my memory recalls: - If your timing is retarded; when cold, the ECU will advance the timing automatically and it will appear to run fine. When warm, the ECU will undo the cold advance and your acceleration with go flat as your RPM's go up.
other thoughts - The timing belt could be off by a tooth, but the cold-warm performance would not change. - The distributor connector is prone to breaking wires. But if you get good power when cold, then both the distributor pick-ups are functioning..
-RRJ
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Post by JustyRally on Feb 11, 2013 2:42:24 GMT -5
Well, i should of stuck with my first gut feeling. Guys at work talked me out of thinking it was the timing belt. I came here asking about a sensor that my cause this. This has been pissing me off. Don't feel bad about the fuel pump it seems to run better now and will run better when i fix the problem.
The belt tensioner spring broke and went around inside the cover. Ended up in the bottom and melting through the cover and the belt has a gouge. Im guessing without the spring it jumped a tooth.. I drive on the highway, high RPM every day to work and that's when this problem occured.
I have been without my Justy to long.
Now that im this far into it, im going to rebuild the water pump and oil pump..i already had the stuff and was going to do it anyways. Can anyone offer any advice on what else i should replace when I have all this stuff off. ......can i get the cover off without pulling the whole engine?
It looks like coolant is leaking around the top of the crankcase cover. The sluge under the oil cap still has me worried, I seem to have a little white milky substance in the oil not much....I have not driven this car, only around the block to see what it would be like after I did things to it....and start ups to get it warm. I never had this sluge under the oil cap before.
Also, shouldn't i see the check engine light when i turn the key to the on position? Maybe the bulb is burned out.
I hope the belt is the only real problem....I have not had time to check the cam/crankshaft sprocket alignment yet..need to get the valve cover off to get CYL#3 TDC. ....im going to adjust the valves also.
Any more advice would be great thanks.
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Post by Armageddous on Feb 11, 2013 10:53:17 GMT -5
Good call RRJ, if he kept listening to me there would be a lot of new parts and no issue solved. You are right with the ECU advancing the timing when cold, due to the rich mixture and the thermic valve being open. After it's warm it goes closed loop and is more susceptible to having a running issue. As far as your crank case cover it can be removed with the engine in the car, it's not even that difficult. You need to break down the timing belt obviously, remove the alternator, take the oil pan off (cross member, lower trans mount) to gain access to the pick up tube, pull the waterpump cover and undo the center bolt for the impeller, undo the rest of the bolts then take the crank case cover off. The only other thing to replace in there is the balance shaft chain and guide once the cover is off. These are the only useful pictures I have for you.. The small aluminum plug in the second picture is something I made to try to improve oil pressure. Terry
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Post by JustyRally on Feb 18, 2013 12:43:32 GMT -5
I have a chain and guide now. I saw in another post about sealing the back side to the block....glad i saw that. I drained the oil and it didn't have anything in it, that was a happy sight.
Is it easy to change the cam seal with it in?
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