Intermittent Spitting and Sputtering

1997 Transport with 184K. Car runs fine then when it seems to get to temperature it start spitting and sputtering and then recovers or shuts off. Sometimes restarts and sometimes it doesn't restart or just barely and then quits. Replaced the fuel pump, did not fix the problem. After an episode of sptting and sputtering will run fine for a bit then if you leave it idle it will just shut off and then restarts fine. No codes show up.

I also noticed temp two marks about 210 degrees then fans get in. The seem at low speed. Didn't know if this was related.

Any suggestions?

GIven the time it took me to figure out a solution to my own problem, I will ask more questions than provide answers....
First....this looks like an ignition problem...."looks like".....so....I would first try to see if I have spark when and if it refuses to start. Just remove a spark plug connector and insert another spare plug grounded to the engine block....this is the easiest test to do to have something to start with.

Does it ALWAYS run OK when it is COLD (& warming up)?

If I had to guess (& I don't like to guess), I would look into the Crankshaft Position Sensor(s). The reason being, I have a '92 Jeep Cherokee (over 100K miles) that had similar symptoms last year. It would just quit. Sometimes it would restart, sometimes not. After several weeks, it finally refused to start and set a code that said "No Reference Signal During Cranking" - or something like that. Replacing the CPS fixed it.

Most of these sensors are "Hall Effect" devices that will weaken over time and with temperature changes.

These are just my opinions & observations. Do with them what you will.

Take Care,

Seems to run and start when cold but quit when it is up to running temp. When it is spitting and sputtering there is spark that is why we were thinking more along the fuel supply issue. We did an injector flush and waiting for results. We will pursue the crankshaft posistion sensor if that does not work. Other suggestions are welcomed. Thanks for the replies.

Well the flush did not work. I am trying to convince everyone it is a sensor issue. Another interesting thing was when it was reved up to 4000 rpm it started to surge. When I pressed on the gas even more it would not go over 4500 rpm and seemed to be missing (spitting). Still no codes. Help.

There is a RPM limiter that acts when you try to floor the throttle in neutral and 4000-4500 rpm is the normal limit implemented. THis is normal operation.

We changed the crank shaft position sensor. No change. We changed the mass air flow sensor.....awaiting results.

As far as the RPM issue would it prevent you then from holding it at 4000 rpm and then suddenly not allow you to punch it to the floor. When I did that it just studdered and would not go any higher.

As far as the RPM issue would it prevent you then from holding it at 4000 rpm and then suddenly not allow you to punch it to the floor. When I did that it just studdered and would not go any higher.
Yes around that limit it just starts sputtering like it lacks fire and will not go higher. ON my son Z-34 it even lingers between 2800 and 3200 rpm on Neutral ...but when on Drive, the sky is the limit.....

I noticed I did not answer and earlier question about SPARK. It has spark even when it starts to act up. Nothing shows on the coputer when plugged in and starts to do this. I was thinking coil pack because it seems to do it when warm but there is spark when acting up.

Well...I suggest you check out my other thread, there may be some ressemblance, except mine just stopped firing up completely; electronics are ALWAYS heat sensitive and can become go/nogo around a given temperature after a while. I do not pretend that the trouble I had will duplicate everywhere starting now but it can be verified at least. My suggestion is to check a fuel injector voltage to verify if you have pulsing ...unplug one , install a load on the plug like a 22 to 47 ohms resistor or a parking light bulb (using a high impedance voltmeter alone can give false readings) and crank. You could see short voltage pulses. ANother symptom on mine is that it prevented the 1 sec injector pulse at KEY ON but the fuel pump did work for that 1 sec. I did not change the coils: just the wafer under.
BTW,what is your distance from Oshkosh ?
http://www.avigex.ca/xport/greenbay.jpg

I am in Green Bay...so 40 miles to Oshkosh.

So are you saying the wafer under the coil was the problem?

In my case, absolutely. I suppose you have looked at this http://www.automotiveforums.com/vbulletin/showthread.php?t=558604
Notice I had changed the crank sensor at the beginning.....while it was not the culprit. I consider I have enhanced the car reliability though; at that age, it seems there is some higher probability that it would fail , so I guess I have moved on the good side of the statistics now.

Well the module below the coil pack was replaced with a used one due to cost and also replaced sensor that runs the injectors. Still having issues. This is tough one.

Hello.

I am experiencing the same problem with the spitting, sputering and no go.

It happens in hot weather. The car is driven by my son and both times he was on his way back to college and the 96 Jeep just died - after the sputter move. Brought it to a mechanic and he replaced a MAP Sensor S - at a cost of $96 for the sensor. The Jeep just repeated the same problem is is back up in Sonoma, Calif now. It runs, but it killed twice on the way up to the college.
Have you had any progress on your problem?

No progress, even got worse. The next move is the replace the harness that is connected to the module under the coil pack. It appeared that heat was an issue but the last time it acted up I was in it for about 4 min and it started acting up. The mechanic said the it appeared the wires on the harness looked in bad shape. It may be electrical because it just does not miss but feels like it is going to shut off but comes back on right away. Will let you know what we find out.

Replaced the harness. Had some bare wires under the insulation. Seems to be working fine. Will drive it for a week and give update.

Well it seems the harness was the problem. Van has been running fine since it was replaced. The 2 wire harnes runs from the coil pack to the computer. The wire coating was melted off and shorting out. It was covered with the plastic protection tubing and was hidden. It seems that over time the coating on the wires got hard, and then with the wire running down the back of the engine, the heat did the rest. Hope this helps someone.

Thanks mkwetam, and all who posted - saved me a fortune! Minor correction - it's the harness from the ignition module to the crank position sensor which is separate from the engine harness to the computer. Getting to this harness is alot of work (4 hrs in and out), so I had the mechanic replace all the components along the way (coils, module, wires, plugs - I got 'em cheap on-line). Here's hoping to that for $750 I'll get another year out of ol' faithful!