I've had a problem lately with my '89 Montero 3.0L where it takes a LONG time to start in the morning... maybe 4 or 5 tries. Since this only happens when it's sat for 12 or more hours, I'm thinking that fuel is draining out of the lines due to a bad check valve. Can I assume that Monty's have an internal one built into the pump? Is this a typical malfunction or am I barking up the wrong tree? I realize that I could be having issues with the ECU or even the pressure regulator -- but I'm not noticing any other fuel delivery problems at any other time. First thing I did was to replace fuel filter without any change. Could this be a sign of the pump about to fail completely? I don't want to deal with the hassle and cost of replacing the pump, but at 200,000 miles -- I have no idea if it ever has been replaced. The manual also talks about testing/checking the "fuel pump drive control system" -- is this referring to the ECUs ability to turn on the pump when you turn the key? I don't understand where this is/how to test.

Just wondering if anyone has experienced similar or has some thoughts on the most logical cause.

Thanks for any help,
Bryan

There is a check valve and also a relief valve - both inside the fuel pump.

Several of the '89 vintage 3.0L fuel pumps have recently been replaced by folks on this forum. It's not a terribly difficult job to replace one - a couple of hours at the most if you don't run into a lot of rust on the access port fasteners. I replaced mine last week with a Denso (OE manufacturer) pump - cost about $120 delivered.

You need Denso # 950-0150 which includes a new filter that's necessary to install if the warranty is desired:

Order Denso Pumps Here

Sometimes, the fuel pressure regulator is the culprit. It requires an hour or so of work to replace, but it takes as much time to check it as it does to replace it. I'd put in a new one along with a new pump if you think either is bad.

It's possible that the injectors are leaking, but that's hard to diagnose without an installed pressure gauge - not practical on our trucks.



Yes, that and whether the relay and pump will work - but since your pump does eventually supply fuel, the ECU and relay would seem to be ok.

Good luck,
Frank

I was wanting to make sure I was chasing the right problem before pulling things, since I wasn't sure how to test for what I thought was wrong -- and I appreciate the link to the right part... NAPA and such list way too many options than could possibly be the right fit.

Thanks again,
Bryan

Could also be the ecu coolant temp sensor, but that should throw a code. If it's malfing, it won't tell the ecu the engine is cold, and the ecu tries to start it too lean. Gets worse as the ambient temps get colder.

I'd try Eddy's suggestion before replacing the pump and/or regulator. It's fairly easy to remove and test the ECT.

I'd also test the MAF sensor - that can do the same thing as the ECT if it's out of range.

Frank

That might make sense since the problem has been occuring now that the outside temp is getting cooler... I'll look for my analog voltmeter and check for a code. I admittedly was thinking is was a fuel supply problem and didn't consider the MPI system.

Thanks guys!
Bryan