SHO no start. Cooling fans on full blast? Possibly CCRM?

[DNort]

TL;DR first

Sometimes when I start my car, but not every time. My fuel pump doesn't sound like it is working and the cooling fans automatically come on full speed.

The car will not start when this happens

Most of the time the car will turn on normally. I'll hear the 2 second prime of the fuel pump, the cooling fans will be off. and it will start normally (Like it is supposed to unless i'm mistaken)

I feel like my CCRM is bad. It is that little box with wires going into it near the right side of the radiator. If I recall correctly that is what controls the Cooling system and the fuel pump.

I know I don't post a lot but I usually try to read before asking questions. You guys have helped me out a LOT in the past and I really appreciate it.

I appreciate any input

Car is a 1994 (2nd Gen) MTX

Thanks in advance

 

[sperold]

Shine up and tighten all the grounds in the engine compartment. Sometimes, when the grounds are weak, the electrical system tries to ground itself using the CCRM relays.

The CCRM itself does not have to be grounded to the rad saddle to work, so don't bother fiddling with that bracket attachment.

My guess is grounds, followed by CCRM issues.

To make matters worse, you can never rule out the ECM as the source of glitchy issues like this.

My 90 has the fans come on for about 10 seconds when I first turn the key, but always go off, but the fuel pump always does the buzz thing. The fan issue has been around for 2 years, and all I have done to remedy it is to buy a spare CCRM.

You will need a D code CCRM.

 

[rubydist]

Your symptoms are typical of a pcm that is not grounded. It may be a ground connection as sperold suggests, or it may be a bad wire in the harness - I've seen both.

 

[DNort]

The PCM is behind the glovebox correct? I checked all of the grounds I could find around the engine bay and they were all still pretty solid (I touched up a lot of them when I first got the car a few years ago)

Is there a ground specific to the PCM? Where would I find this?

 

[rubydist]

Correct, pcm connector is on the firewall ahead of the glovebox area.

What I would do is disconnect battery, then disconnect pcm connector (use care to not break the connector) then check resistance to ground of pin 20, which is the ground circuit on your pcm. Pin 20 is on the end of the top row, opposite pin 1. You should have almost no resistance to ground. If that is not the case, then you need to chase down why.

 

[DNort]

Awesome! Thank you so much for the help! I'll do this over the next few days and hopefully it will be an easy fix. Hopefully it isn't some stupid cruddy wire somewhere mid harness that is giving me grief.

Thanks again

 

[DNort]

I checked some things but I didn't get a lot done because It started raining. I figured even though the battery was disconnected doing this sort of thing in the rain is asking for trouble.

I disconnected the PCM connector with relative ease But I was having trouble getting it up high enough to be able to test the pins with the volt meter. I didn't want to force anything because that just seems like a bad time.

Pin20 is on the top row, so is it on the far right or the far left (Driver side or passenger side?)


I put it all back together as it started drizzling and the car was able to start up again the way it was supposed to. I did clean up some grounds I saw near the battery and the back of the firewall so that may have helped... Or I have a problematic wire in the harness that sorted itself out a bit as I was jiggling it all around.

I do plan on fixing this Properly as I don't want the car to leave me stranded somewhere.

 

[rubydist]

don't remember which end of the row it is, but pin 1 is power so it will be very clear which is which when you ohm it out.

 

[DNort]

Good point! Thanks so much!

 

[DNort]

Guys I'm at a loss. I check the ground on pin 20 and it is like .05 ohms resistance. I've checked all the grounds in the car and it still does this random full blast fan thing on startup.

Neither the PCM or the CCRM smell like I let the smoke out. But the grounds are fine and the resistance is fine.

The car even starts up and runs most times but sometimes it doesn't.

I just checked the resistance on pin 20 again. Near nothing. But right now it still wont start at all

 

[luigisho]

I would look for a working used ccrm and see what happens. That thing is hooked to the cooling fans and the fuel pump. Could be wiring and stuff but this something you will always want in reserve just in case, and can sell easily if you need to.

 

[DNort]

I just bought one from shosource. I thank you all so much for your help. You guys are all great.

The car is my daily driver so I want to get it going again.

You're all awesome and I hope it works out!

 

[DNort]

So I was looking at this picture of the PCM pinouts http://puu.sh/uatYg/de15552c33.jpg

Pin 20 is the case ground (which I was told to check and seems to be grounding just fine.
Should I also check ground resistance for pins 40 and 60? They are called "power" grounds and I don't know if they function the same way.

 

[rubydist]

that would be good to check too.

 

[DNort]

I checked all 3. They all seem fine.

I installed a new D code CCRM

Car still doesn't work.

Would my next bet be a new PCM? Or should I get the car towed to a garage.

I really can't afford to keep throwing money at it right now.

Car is being stored at a friend's garage. It needs to be gone in the spring when his Porshe 911 turbo S gets back from the shop.

So new PCM or tow it?

 

[sperold]

The "garage" is not going to find your issue if you can't.

Forget the tow and get another PCM from someone on this forum, maybe Dan Barbush (SV&HOdan). I think he is in your state, and he knows a thing or two about SHOs.

Follow all the advice that Rubydist has / will offer and get an Electrical and Vacuum Troubleshooting Manual (EVTM) for your 94 from E-bay. It will give you the confidence to pull back some tape on the harness near the connectors and have a look at specific wires for issues.

 

[DNort]

I moved to Canada and with the tarrifs getting parts up here is super expensive. I'll try a PCM and if that doesn't work I'll have more of a look at the wiring.

I added more grounds from the negative battery terminal to all over the body hoping that would help. But even still I have next to no resistance from pins 20, 40 and 60.

My check engine light doesn't light up anymore either. And sometimes my PCM makes buzzing and squeaking noises. So I think that is a good thing to check.

The car went from working most of the time to working not at all now. So I'm really hoping that a PCM will fix it.

The Canadian government put a lien on my car too so I can't even get rid of it.

Worst birthday ever

Thanks guys.

 

[sperold]

Welcome to Canada; and that was a nasty first interaction with our government.

I get my parts from the USA and have them shipped to the nearest UPS store in America, and I drive over and pick it up. Usually are no taxes / fees payable at the border unless you are dealing with hundreds of dollars. Take the ferry over to Barr Harbour if you have the time and the crazy high fee.

If you are far from the border, I would have the used part mailed into your post office and pay the HST on the low amount it will be. On that part, you can probably get away with a padded envelope, and have the seller enclose a receipt that does not include shipping. They will open the package and take a look, but it will not be any grief for you.

Happy birthday, and don't give up the ship.

 

[DNort]

GREAT NEWS! The new pcb made the car happy again! All is well! And for some reason this made it through the border without being taxed! (I had to pay 50 dollars extra just for the ccrm)

Put the new PCM in the car and it is good as new!


I took apart my old PCM just because it is broken anyway, so why not!?!

Look at what I found!

That looks like a blown cap to me! I may try and replace it just to see if it works. That way I have a spare. I don't think the new one I have will go bad any time soon but it's always good to have options!



Thank you all for all of the help. I read on this form occasionally and I am so grateful that you've all taken time out of your day to help me with my silly little problems. It's great to keep as many of these cars on the road as possible!

 

[SHOdded]

Can always ask CircuitBoardMedics.com for repair pricing. Prevent a salvageable ECU from being junked.