fuel pump?

[munkee]

Hi there. I just got back from a quick (2400 mile) trip to Montana and back in my friends 91 mtx and it was having some problems I am not sure about. First of all, we ran out of gas when the gauge was barely touching the E. It only took 15.7 gallons to fill it to the top of the nozzle and I know it has the 18.whatever gallon tank. It died going through a wendys drive thru so i know the tank wasn't tilted. What would keep it from using the bottom 3 gallons? It also has a hard time starting on occasion. It will crank and crank but won't start until you give it some gas. Other times it fires right up. You can hear the pump run when you turn the key on but it sometimes makes a gargling sound towards the end of it's cycle. Is the pump going out?
Also, we drove all the way over with two of the plug wires popped off. Didn't catch it until we got there but it explained the missing under heavy load and having to downshift going over the passes. (Still managed to toast a GTP with only four cylinders! burn_out ) There is oil in the plug wells too but once we plugged the wires back in there was no more missing, it stayed in 5th just fine over all hills, and went from 21 to 26 mpg even going 90. The plugs and wires are the motorcraft parts but the front and back wire on the drivers side keep popping off. Could that be caused by a bad motor mount? Anyway, it has 196000 miles on the motor and it has only had one 60k. This winter when we are layed off we're going to put a new motor mount in plus do a 200k service. Any advice is appreciated. Thanks

<small>[ July 28, 2002, 09:47 AM: Message edited by: munkee ]</small>

 

[BeatDaSHO]

as for you running out of gas........it was probably the cps. Your water pump is probably leaking coolant right onto the cps which is shorting it out. You probably thought you ran out of gas because when you tried to start it again, it would just keep cranking. Then when you filled it up, the cps had time to cool down so when you started it, it started fine. Then when at wendy's, coolant probably leaked more and then it stalled out right away. Replace the cps, water pump, and while your in there, you might as well replace the timing belt and front main seal. Now, to explain the popping of the wires. This is caused by oil in the plug wells. Replace the plug well seals and valve cover gaskets with the felpro gasket set at www.autozone.com. Get the motorcraft agsp32pp plugs for your SHO also. If you are over 100k with the wires, you might as well replace those. if not, just clean them real good. You are looking at about 200 dollars to fix this all. TRUST me, it will be well worth it.

Greg

 

[projectSHO89]

You can hear the pump run when you turn the key on but it sometimes makes a gargling sound towards the end of it's cycle. Is the pump going out?

Yes. That gurgling/rumbling sound from the gas tank means the check valve in the fuel return line has failed. That allows the pressure to bleed out of the fuel system when you shut the car off and contributes to extended cranking time at startup as the FP has to repressurize the entire system. "Giving it some gas" should have no effect on initial starting on a fuel injected engine, as the gas pedal only opens the throttle body plate (and causes the TPS output to change), it doesn't actually pump any fuel into the system as did the carburated systems of older days.

Reportedly, some SHOs got the standard 15.x gallon tank instead of the 18.x one. Depends on whatever the Atlanta factory had on hand, I guess.

Your symptom if intermittent start/no start can also be a symptom of a failed camshaft sensor (CID). If the DIS/EEC-IV does not see the CID, it guesses at what signal to generate and has a 1 of 3 chance of getting it right.

Here's how to test your motor mounts: http://www.shotimes.com/SHO3mount.html

Steve
89

 

[munkee]

Well it did definitely run out of gas. We replaced the cps and clutch about two months ago when he bought it and the water pump was replaced a year ago. We planned on replacing wires and gaskets when we did the 60k this winter I just didn't want him to ruin the cats by running raw fuel through them since the wires keep coming off. Anyway, I guess we will replace the fuel pump while we are at it. Thanks for the help.

 

[sdpatt]

A bad motor mount does not cause this. It creates its own problems though. The plug wires are popping off probably because they don't fit properly. I have seen one set of 3.2L Motorcraft wires that had this problem. Poor fabrication quality on that set, but it may have been an isolated condition. I have not seen this on any of the 3.0L wires, but you may have one that was made with that bad Friday batch.

The low frequency, gurgling noise usually happens with a hot engine on a restart. This is caused by the fuel return line check valve that no longer holds adequate pressure in the return line. This lower pressure allows the fuel to become vapor and bubble up through the fuel in the tank. This usually causes an unsteady idle until the fuel pump gets some cooler fuel in the return line. This is not a real driveablility problem, but it is a bit of a nuisance on hot restarts. Search the Forum for the part number of this little check valve. The fuel tank must be dropped to replace it and it is on the pump assembly. You can wait until the pump needs to be reaplced before swapping it.

You need to replace the spark plug well seals to keep the oil out of the plug wells. These seals come with the Fel-Pro VS50378R valve cover seal set for $71.99 from AutoZone.com. You will find them for the 91 SHO in the Engine External -> Valve Cover Gasket path. You need to remove the intake and valve covers to replace these seals, so you should also perfrom the long overdue valve gapping while you are in there.