Engine tries to stall after cooling fan cuts off

[searcherrr]

Title says it all: "Engine tries to stall after cooling fan cuts off"

and

Van doesn’t hold steady idle in park or at stops, idle goes down and bobs up and down continuously in park with wheel turned and still bob's slightly (but less so) with wheel straight, idle goes down and bobs up and down continuously when a/c on. Ironically it does not try to stall when the cooling fans kick ON; only when the fan(s) cut off.

Idle air controller motor?
CCRM (Constant Control Relay Module)?

The thing is the IAC motor is brand new within a year although I just went through a horrible engine experience (bought defective engine, had to take it out, put new engine in again) and I'm wondering if the motor or some wiring got screwed in the process. Would the CCRM had to have come out to do the engine installation? I am HOPING to GOD it is the IAC motor because that should be still under warranty.

[wiswind]

The CCRM module is not in the way at all.....it is on the radiator side support.....next to the ABS module.
It contains the fuel pump relay....so if the unit is not connected, it would not run.
If this is your original CCRM, you might try replacing it.....if the IAC thing does not work.
They did update the unit since the vehicle was built.....better sealed relays in there....so I would not get a bone yard unit......as you would want to get the improved version.
The original issue that caused them to update it was a issue with the fuel pump relay in below freezing conditions.
I have pictures posted of the CCRM
I have replaced mine 2 times.....once for radiator fan issue and once for A/C compressor issue.

The first thing that comes to mind is the IAC (Idle Air Control).
As it is new, you could try cleaning it.....with SeaFoam "Deep Creep" (which is the spray version) or even WD-40.

[searcherrr]

Originally Posted by wiswind

The CCRM module is not in the way at all.....it is on the radiator side support.....next to the ABS module.
It contains the fuel pump relay....so if the unit is not connected, it would not run.
If this is your original CCRM, you might try replacing it.....if the IAC thing does not work.
They did update the unit since the vehicle was built.....better sealed relays in there....so I would not get a bone yard unit......as you would want to get the improved version.
The original issue that caused them to update it was a issue with the fuel pump relay in below freezing conditions.
I have pictures posted of the CCRM
I have replaced mine 2 times.....once for radiator fan issue and once for A/C compressor issue.

The first thing that comes to mind is the IAC (Idle Air Control).
As it is new, you could try cleaning it.....with SeaFoam "Deep Creep" (which is the spray version) or even WD-40.

What was the a/c compressor issue? Along with all the recent engine work I had them replace the clutch and all related/assembled connecting parts. They evac'd and recharged the freon system and it seems to work well, but not as cool as it used to. I'm curious though if you think the compressor may be bad though there is no noise or a/c failure to make me think so beyond it not being as cool which may just mean adding more freon.

I'll go read your CCRM sticky, but what was your radiator fan issue again? I'm sorry to ask cause I know you must've covered this a hundred times already, but I'm at a coffee shop and battery going low. thanks again wiswind !

[wiswind]

My radiator fan issue with the CCRM was a strange one.....the fans would not come on unless I turned the A/C on.....regardless of engine temperature.

As far as the A/C refrigerent system, I feel better letting a good shop diagnose that.
They have the equipment and know how to do it.
In Wisconsin, you have to be licensed to do A/C work.
In fact......until last year, you could not even buy the refrigerent unless you were a licensed shop......not available at the auto part stores, etc.

[96wWindstar180K]

searcherrr
If you have a fuel pressure tester (available from Sears about $30.00) you could test your fuel pressure. It should be about 40 lbs. You could also try unplugging your fuel pressure regulator. As long as the problem is happening at idle and your not cutting out at higher rpm it could be a combination of the ccrm, fuel pump or vacume regulator or even the fuel pump. I only think its not the IAC because you already replaced it. Check the fuel pump pressure first. Is that your original pump? Hook up the fuel pressure gauge with engine off and once connected turn the key to the on position the gauge should read about 40 lbs. If it only goes to 25 lbs try turning the key to the off position and back on again and see if the pressure goes up. If so the fuel pump is going bad. If it was at about 40 lbs start the engine and watch the gauge as the fans cycle on ad off. Is the fuel pressure dropping? Now unplug the fuel pressure regulator with the car idleing again watch as the fans cycle. Is there any change? Now acclerate the engine with the vacume hose removed from the vacume regulator and vacume hose plugged the fuel pressure should go much higher and fluctuate because the regulator is removed from the system. These processes wil just help you rule out the fuel pump and regulator. Post back your findings.

[searcherrr]

Originally Posted by 96wWindstar180K

searcherrr
If you have a fuel pressure tester (available from Sears about $30.00) you could test your fuel pressure. It should be about 40 lbs. You could also try unplugging your fuel pressure regulator. As long as the problem is happening at idle and your not cutting out at higher rpm it could be a combination of the ccrm, fuel pump or vacume regulator or even the fuel pump. I only think its not the IAC because you already replaced it. Check the fuel pump pressure first. Is that your original pump? Hook up the fuel pressure gauge with engine off and once connected turn the key to the on position the gauge should read about 40 lbs. If it only goes to 25 lbs try turning the key to the off position and back on again and see if the pressure goes up. If so the fuel pump is going bad. If it was at about 40 lbs start the engine and watch the gauge as the fans cycle on ad off. Is the fuel pressure dropping? Now unplug the fuel pressure regulator with the car idleing again watch as the fans cycle. Is there any change? Now acclerate the engine with the vacume hose removed from the vacume regulator and vacume hose plugged the fuel pressure should go much higher and fluctuate because the regulator is removed from the system. These processes wil just help you rule out the fuel pump and regulator. Post back your findings.

Q: I think the most important question here is: Why would the engine try to STALL when the fans go OFF? There is no electrical load (that I know of?) when the fans go off so I'm at a loss.

I was afraid someone would mention the fuel pump as it is the original as I'm sure is the regulator, though again I'm not having problems while driving..... HOWEVER today there was a "shutter" when I was throttling up onto a road HOWEVER just a few minutes prior I was checking and moving electrical connection at the NEGATIVE post at the battery which I found to be LOOSE (moveable by hand with moderate effort) and corroded. I took it all apart sanded/wire brushed, and cleaned it all and made sure it was good'n tight and coated with protectant.

Perhaps the new engine running so well is putting higher and/or "correct" demand on the fuel pump and/or regulator and now it is having a problem meeting that demand. I guess I could always try a can of seafoam in the gas tank too as the fuel pump sat for 2 months and then 2 months again without being used.

I have a fuel/vac pressure tester gauge.

Q: Where is the fuel hose to check pressure at or the fuel pressure regulator?

Q: Do I hook up to a vac line to the fuel pressure regulator or to a FUEL LINE to it?

Also, I swear that I do not have the "passing power" that I had before the new engine was put in.

Q: Still wondering about the rear bank cat converter - had glowed red after 85 mile trip before new engine was put in - If it is partially/mostly clogged could it cause this stuff?

[searcherrr]

I resecured the negative battery post after sanding the contact points and cleaning them up.

I took off the IAC (which is very new) and it was not clogged at all. I'd say 98% clean. I don't know how the rod inside is supposed to feel, but I could move it back/forth till the point that the air stopper plugged the valve. Seemed like it was ok to me, though I cleaned it up well anyway with electrical parts cleaner.

NO CHANGE.

I want to know what is causing this, but at this point its the shop's deal as far as I'm concerned. I couldn't give it to them today cause they were backed up and short staffed so I'm bringing it in tomorrow.

[searcherrr]

Great. I brought the van back for the shop to look at it and I think they're tired of me cause they said I just need to put some miles on the new engine and the problem should resolve itself. It drops all the way down to 500 RPMs when this attempted stall happens. They said they don't believe its a fuel pump issue or the regulator though BOTH are still the original units at nearly 158k miles now.

Think I should just drive it around and wait n see? I mean it has not ONCE actually STALLED out. It does just "try to".

[wiswind]

I still have my original fuel pump at over 193K miles.
I have a different pressure regulator, but only because I replaced it when I was trying to track down a slight miss.......and it was not the problem...

Point being, they could well still be just fine.
The problem does not sound like these 2 items would cause that.
I am guessing that the shop is thinking that your PCM needs to learn the drivability information.

[searcherrr]

Well today I figured I am getting EXTREMELY bad gas mileage. I have used 3/4 of a tank and I reset the trip odometer as I always do to zero at the pump after filling the tank full and I have only gone 180 miles. I know I have a 25 gallon tank and that typically on the highway I should come close to 400 miles per tank especially with the new Jasper engine.

At this point the title of this thread may be slightly off cause of what I'm thinking. If you take 25 and multiply it by 3/4 (.75) you get 18.75. 180 miles divided by 18.75 is a horrible 9.6 MPG and I do believe my math is correct here. I'm going to see what the remaining 1/4 tank gives me, but even if it gives me 100 more miles before absolute "EMPTY" just below the E mark thats still a good 100 or so miles short of what I should be getting out of it. I got 200 miles per tank when I was towing 3000lbs before the overheat in October last year so I know something isn't right.

From those who followed my overheat/breakdown engine debacle in the other threads (http://www.automotiveforums.com/vbul...d.php?t=771924 & here: http://www.automotiveforums.com/vbul...d.php?t=771428) you would know that one of the things I noticed when I drove it home was the glowing red rear CAT from a misfiring cylinder #5. I drove it a good 100 miles in this condition. I just went and read this at HowStuffWorks:

How do I know if my catalytic converter has failed? - http://auto.howstuffworks.com/question482.htm

And as my shop and I were initially worried about replacing the CAT(s) and/or O2 sensors we'd decided to see how the van would run first. Its seeming now that the worst may be realized in that I can't even get away with leaving the exhaust system alone in this debacle that is seeming like it will never f'in end. I have noticed some "shuddering" from time to time while driving, but I always attributed it to the faulty-prone AX4S trannies we have even though mine is only 20k old from a rebuild now.

Since the new engine installation there have been no overheat conditions or glowing CATs, but but but but I HAVE noticed the engine running a LITTLE bit hotter than my old one did before the head gasket went out. Operating temperature was ALWAYS and I mean ALWAYS right dead smack between the M and the A on the temp gauge and since I've gotten the new engine it has been dancing up to the "M" - midway of the letter and sometimes to the left/beginning side of the "M". The cooling fans kick on and cool it off and then immediately when the cooling fans TURN OFF the engine seems to have a problem running idle and tries to stall. I am wondering now if this is because of a build up backpressure due to the partially clogged cat. TO ME (someone tell me if I'm wrong here) a partially clogged cat condition would seem to only reproduce itself during a low RPM condition or just at idle itself.

In any case I have no way of knowing the extent of the damage the 100 mile driving did when the cat was glowing red when all this started, not to mention the CAT had already been used for 157,000 miles prior. This also could be an O2 sensor, but I'm having a problem believing if it was that the gas mileage would be suffering this badly. This is almost HALF the MPG I used to get.

What ya'll think? How do I test for a bad cat? Just let it run idle a long long time? Is there a tool I could use?

[garync1]

My exhaust shop up the road test cats for free.. So call around and ask some muffler shops if they do the test and if its free..Good thing is my guys are honest.. I sent many of people to him and not one tested bad. Although Im sure he would be happy to replace them anyway.

[wiswind]

I would not rely on your mileage check.....
I go by how much fuel I add to the gas tank to get the pump to shut off........Divide by the miles on your odometer, which is the miles since last fillup with your reset at each fuel up.
THEN average it out over a few tanks of fuel......as you will have some one tank wonders......and some one tank losers......
Fuel economy checks this winter here in Wisconsin have been worthless for me as it has been cold.....too much slow and short trip driving to expect a good number.

Temperature........it is possible that the sending unit for your gauge is different than it was.
I would want to know what the PCM is seeing.....which I monitor with my Scangauge.
I find that my temperature is VERY stable.....at 191-194 degrees F......might swing some at idle.....stopped.

This check will tell you if you have a gauge, sending unit problem....as the PCM uses a different sending unit.

If the temperature is really swinging more than it should.....it could be a thermostat issue, or maybe a bit of air still needing to burp its way out of the cooling system.

Catalytic converters.....I am guessing that they are working.....as you should get a CEL if they are not.....
Each Catalytic converter has a oxygen sensor that is there ONLY to monitor the catalytic converter to make sure that is is working.....if the sensor is not working.....there are a bunch of codes for that also.
A check to see if the OBDII system shows "READY" will confirm this.....with my Walker replacement catalytic converters, I found that it takes a long time for the downstream oxygen sensor part of the OBDII drive cycle "self test" to complete......even up to a month.
My Scangauge indicates "Not Ready" until this drive cycle test is completed.....then is shows "Ready".
As garync1 indicates.....a number of shops are out there that can test the catalytic converters.
The thing that you might want to get checked......is to see if there is excessive back pressure.
I would think that this could be checked at the DPFE connections for 1 catalytic converter.....not sure about the other one....unless they tapped into where the upstream oxygen sensor is mounted.

[searcherrr]

Well, its gonna go back to the shop that installed the engine for sure after I verify the next tank is burning too much gas as well.

The good thing is I've already located a dual-cat pipe setup and exhaust upgrade I want. I looked up all the possibilities before the engine was installed so I'll just order it if that turns out to be it.

[wiswind]

I have a picture of the OEM next to the Walker "direct fit" unit that I installed 3 years ago.
http://rides.webshots.com/photo/1291...11220610mzvEni

Exhaust work is not a fun job.
When the flex pipe (connects to the back of the Y pipe assembley......between the Y pipe and the muffler) is disconnected......support it with some wire, etc......do NOT let it dangle as it will damage the flex part of it....

OEM for my '96 lists at about $1600, the Walker was less than $300.
However, OEM is the best....from what I have read.

[searcherrr]

Originally Posted by wiswind

I have a picture of the OEM next to the Walker "direct fit" unit that I installed 3 years ago.
http://rides.webshots.com/photo/1291...11220610mzvEni

Exhaust work is not a fun job.
When the flex pipe (connects to the back of the Y pipe assembley......between the Y pipe and the muffler) is disconnected......support it with some wire, etc......do NOT let it dangle as it will damage the flex part of it....

OEM for my '96 lists at about $1600, the Walker was less than $300.
However, OEM is the best....from what I have read.

Thanks for the comparison pic man. Thats really cool to see the flow design differences/improvements.

Yeah, i agree OEM is best, but I can't help but see how the design of the Walker one and others flow better and if we are talking about like the OEM lasting 300k miles vs 3rd party like 150k or 200k or something like that then I really don't care especially when it comes to saving about $1300. I mean shit.. I could buy a whole other engine for that price!

Thanks for the tip about the flex pipe though I think if I'm gonna do this I'm going to do it all the way back. I have found a discontinued closeout going on. Borla cat-back exhaust system for our Winnies and its priced very very reasonably I think. I want something higher flow from the ypipe on back. The only thing that pisses me off is that I can't change the header pipes unless someone fabricates them for me very cheap, but that I'll have to live with.

All others please move this discussion to here: "Bad cat or not?"

Moved a 2nd time to here (though there's good cat checking info at the thread link above): Attempts stall, Idle Pulses 600-800 rpms, horrible MPG