Well driving to a friends place for dinner last night and out of the blue the car starts loosing power. I could pump the throttle and keep it running but not well.

I checked all the wires, and hoses. Cap and rotor look ok. So from what I can tell, it's getting some spark and fuel, just running poorly. Seemed like when it 1st died the pumping was more effective.

I'm thinking MPS diaphragm died. I'll be able to test after I pick up a vacuum pump in the morning. It has gas in the tank, but until I can actually check pressure I will not know for sure. Thinking it's ok.

It just came on suddenly as if a switch was flipped.

Figured I'd put this out there for the brain trust.

1) when did you change the fuel filter?
2) pull off the hose to the MPS, suck on it. Does your tongue stick to it?
Backyard test to see if the MPS holds a vacuum
3) head temp sensor (test it cold, in the morning, then hot after the motor warms up
4) TPS ( not likely)

When I first bought my car it was not running, but it had spark. When I sprayed carb cleaner/starter fluid into the intake and cranked it , it started and ran but just for a bit - after going thru everything, it ended up being a bad MPS - the PO had left the car outside, and the MPS was mounted upside down with the weep holes up, it had water in it , so it was shot. - definitely check it. and on one other occasion my pump when, so - do you have a fuel pressure gauge? after having other issue with failing MPS's( I have had them fail rich and fail lean!) it can help to know the pressure as well to sort thru the issues - one time I was so frustrated because it would start one day and run fine, then a few days later not start. I could not figure it out. So I took it over to the mechanic(Bob Woodman, here in Beaufort) and as he was checking thru it all he accidentally unplugged the MPS and it ran- somehow it was failing lean , the signal it was sending plugged in was way too lean(electronic failure I believe, I don't remember all the details) - so just to keep that in mind.

other than that a short in the ignition would cause it to suddenly stop andnot restart - could be a number of things.

"Whats my problem? Too much Bar B Q"
-Big Twist

I use a mighty vac to test the diaphragm. Easy to control, and the gauge will show the leak if it is there.

"2) pull off the hose to the MPS, suck on it. Does your tongue stick to it?"

This is not a reliable method of checking the MPS. Sucking on the MPS port with your mouth creates very little vacuum to test the MPS and leakdown cannot be detected this way. Even a leaky MPS will function for awhile even though it may be rich.

Check for spark first. Then put some gas in the throttle body and try to start it. If you have spark and gas and it doesn't start, check the cht is firmly plugged in. Mps with no vacuum will be very rich, but should still run. Do you hear the pump run when you turn the key?

And check fuses and relays and connections on relay board.

I'll be playing in a few hours and post the results

Dizzy trigger points dirty...

Oops I forgot in the form of a question!

I'll take D-Jet for a 100 Bob.
What is dirty trigger dizzy points?

broken diaphragm would not make it run poorly, just a bit rich, so cannot be that, I would pull one wire of the cap at a time and see if one does not make a difference, that is where to start. Also have you checked the valve adjust recently?

Mark.....

This might be the famous bad CHT ground problem also.

Check the ground continuity and the CHT resistance profile.

The car WILL NOT run well if the ground resistance is wrong and won't run at all if the ECU does not see a ground. Assuming this is D-jet.

All other comments I've seen apply as well.

Rob

First check all wires and hoses. Are they connected? Has anything popped loose? How about something disconnected but the outer connector is still in the right place? (Wiggle the wires!)

Then check for spark.

Then make sure you've got fuel going into the engine. Is there a fuel smell at the tailpipe after you've been cranking the starter for a bit?

How about compression?

The engine needs fuel, air, and spark to run. If it has those, then you check how much fuel, and when the spark happens.

Problems that happen suddenly are often electrical in nature. Something has gotten disconnected, or something has burned out or melted.

--DD

I'll get back to this today. Spent may day helping Scott ship out orders thanks for the business. I'll keep ya posted

Good thing I know where to get a CHT that's new