Question
HI, ROLAND
HI, ROLAND
I'M STILL HAVING TROUBLE STARTING THAT DODGE VAN.
I INSTALLED A NEW MAP SENSOR ON FRIDAY, BUT IT DIDN'T CHANGE ANYTHING.
LETS REVIEW WHAT I DID SO FAR
· NEW FUEL PUMP
· NEW FUEL FILTER
· NEW SPARKPLUGS
· NEW SPARKPLUG WIRES
· NEW AIR CLEANER
· NEW OXYGEN SENSOR
· NEW MAP SENSOR
NOTES:
· IT WILL START WHEN ENGINE IS COLD
· IT WILL START WHEN ENGINE IS HOT
· BUT IT WILL NOT START WHEN IS HOT, AFTER ENGINE HAS BEEN OFF FOR 20 MINUTES .
TALK TO SOON
CHUCK
AnswerHi Chuck,
I am sorry to learn that the MAP sensor didn't help, but don't despair those do go bad and so you will have a spare when it happens.
I've reviewed the exchanges we have had and come up with the following ideas:
I would bring the engine operating temperature up to fully warmed up so that the temp gauge is mid-scale or thereabouts (i.e. the thermostat is fully opened and assuming you have a 195 thermostat that the temp of the coolant is in the range of 200F) Then remeasure the coolant temp sensor resistance, it should be 700 to 1,000 ohms, and you got 1700 the first time when you described the temp as being warm. I would feel better about that sensor if I saw it was reading 1,000 ohms when you have driven the engine far enough to call it hot. If it won't get down to 1,000 then I would be suspicious that it was the cause of the hard starting when you have let then engine cool down for 20 minutes. That sensor is critical to the mixture control so if it doesn't get down to 1,000 under those conditions it will probably not give the proper mixture for all such restarting conditions. One further thought along this line is that one thing that happens when you start cranking the engine the coolant is pumped thru the engine and probably changes the temp of the coolant temp sensor and thus its resistance. Maybe that is why the engine then restarts, following the recalibration of the mixture by the controller in light of the updated data from that sensor. It's a possibility and may lend credence to my concern over the accuracy of that sensor.
Also, I note that I am not equipped with a '94 3.3L manual but rather ones for '91 and '92. There is a second temp sensor used in the '91 (but not the '92) called a charge temp sensor which is a device that is like a throttle body temp sensor in that it is supposed to help under exactly the conditions which you are have a problem with (warmed (or hot?) restart). So you might look around for a temp sensor mounted on the intake manifold behind one of the struts between the intake manifold and the cylinder head, also near the egr valve tube, which is where it is shown to be located on the '91 3.3L. If you find it, it has the same resistance/temperature spec as the coolant temp sensor.
Finally, the issue of a temp-sensitive vacuum leak might be worth pursuing. I don't know if you have the manual for '94 or not but maybe if I sent you the pages from the '91 manual which gives you a rundown on systematically going thru the fuel system for visible problems would get you started and you could also look for vacuum hose leaks as you went along.
Those are my ideas at this point in time.
It is obviously something subtle, like mixture not being just right, because it will restart,it just takes a longer time cranking to do it, correct?
Let me know if anything interesting comes up or the problem is solved as that is how I learn too.
Roland
