[RoadShreader]

OK....I'm a new comer to the BMW fanatic club. I recently purchased a 1997 BMW M3 for my wife. It's a beutiful car and has 67,000 documented miles. Car Fax history report is clean as well.

Here's my dilemna, like any used car, I have a few issues. The car drove great the first week. However, now I have the check engine light on and the car has lost a lot of power on exceleration. It feels almost like the clutch is slipping in a mean way. I fail to beleive it's the clutch because it drove like a champ one day and the next day it drove like crap.

I took it to a mech (local "do-it-all" mech) and he pulled the codes from the car to diagnose the problem. He told me that he didn't have the test cables to continue the troubleshooting neccessay to pin point the actual problem. However, he feels he narrowed it down to either the MAF or ECU. Well I just installed a used (guaranteed good) MAF and the problem remains. "Yes," I could take it to the dealer (1 1/2 hours away) and have them diagnose it. However, I'm in high hopes I can get a few opinions from you guys who have a lot more knowledge on the car and may be able to assist me based on my description of the problem.

When did the problem erupt?: The problem came about after I detailed the car. In the process I cleaned the engine with the spray on "GUNK" and hosed it off. Aditionally I performed an oil change at the same time.

I'm going to cross my fingers and hope somebody may lead me in the right direction in the effort to correct the problem. The car is just too nice to get frustrated and jump to the conclusion that I just purchased a lemon.


Steve.

[badgtho]

Steve,

you broke a cardinal sin of BMW ownership.. you never got a prepurchase inspection.. and carfax is not worth the paper that it's printed on.

that aside... you've got some problems. it is unheard of for either a MAF or an ECU to fail at that mileage.. and i have never seen an ECU bad on one of these cars without extensive water damage. i would certainly not spray the ECU with water.. maybe thats what happened? did your mechanic check the voltage to and from the MAF? how about any other sensors? if you were banging around with a hose under the hood who knows what you could have gotten wet.

the car should go to a BMW dealer or a private BMW specialist for a full evalutation.

with regard to this issue.. who is your mechanic... mickey mouse? any Autozone or Advance Auto can pull the codes for free and tell you what part is bad.

this is not a car where one guesses and checks.

[99M3Riverside]

^^Most definatly a PPI is important. You have to look forward now. Assuming you had a PPI and it was not a lemon then, you might not have bought one, but you could have created one when you cleaned the engine bay.

If I was in your shoes, I would buy a Peak Tool to do code search and to clear codes on your own. They are around $150. Next, I would check all the electrical connections to make sure you did not get them wet. You might also want to check the Vanos Silinoud (? Spelling) connection. I am not sure if that would throw a CEL. It is up front by the oil filter, maybe you got water in the connection. Check the plugs as well. You might want to check to see if water got to the ECU. It is on the passenger side uptop in the firewall I think.

[RoadShreader]

Badgtho,


I appreciate the quick feedback. No, I didn't get the car looked over by an expert. However, I'm not a notice on mechanics and I'm a pretty good judge of vehicle condition. However, I'm sure an expert eye coming from an experienced BMW mech would have been the optimal decision. However, you'd have to see the car in person to have the respect for it's condition both exterior and interior. I can't tell you that the mech I took it to had the knowledge that I'm after but he gave it a go and didn't charge me a dime. However, I'm out $150 for the MAF which proved not to be the defect.

As for engine cleaning, I can't tell you how many times I've detailed a cars engine utilizing the same process and never had an issue. Please don't tell me the M3 is so delicate towards water in the engine bay that I may have caused a problem. I hope that's not the case. I'll beat myself up for a long time if it is.

I fail to beleive it's the ECU as well. However, at this point I'm at loss. Maybe I will schedule an appointment to take it to the dealer. However, I'm stuborn and wish to exhaust all efforts in the attempt of correcting on my own doings. Once again I thank you for your input.

Steve.

[badgtho]

Steve,

i am really competant backyard mechanic.. and even i got a PPI when i got the car. i've got like 7,000 posts on here and i still ask questions. this car still perplexes me, and even i seel professional advice from time to time. this is not your daddy's olds. this is a complex car with complex fragile electrical that you just took a hose to.

if you know your way around the hood, then you'd know not to guess and check with expensive parts. you'd have got your multimeter out, or asked your mechanic to, and you'd have checked voltage on that MAF. for all you know the MAF was good, and connecting it to a wire that's now corroded burned it out... that does happen.. alot... and normally under those circumstances.

i don;t care how many times you've detailed cars.. DON't get the underhood of this car wet unless you know what you are doing. the ECU in this car is highly succeptable to water dammage (though moreso on the 98-99s)

if the ECU is bad, then it will be giving numerous falty voltages and will trash new sensors as soon as you install them.

i would spray the entirety of the electrical connections with WD40. i would take the battery out and let the car sit in a warm dry enviroment.

i doubt its the vanos solenoid.. that would not trigger a CEL.

you got something wet.. maybe the crank sensor, make the ECU, maybe the MAF.. maybe all of them.

to further/// i'm sure the car does look nice.. but right now that's not worth too much.

[mighty-dog]

A couple of weeks ago, there was a post here for a similar issue that a member had. It turns out that he had cleaned his engine with cleaner and high-pressure water. Upon checking the recesses into which the spark plugs go, he found residual water and cleaner. When he wiped all this out, his car ran normal again. I suggest that you check the same area.

Also, it's worthwhile to get the Peake code reader. You certainly get a good clue of the system that threw a code. I've saved myself a couple trips to the shop and save some $$ because I was able to determine and fix a couple easy issues myself.

[M3@NYC]

Originally Posted by RoadShreader

When did the problem erupt?: The problem came about after I detailed the car. In the process I cleaned the engine with the spray on "GUNK" and hosed it off.

Bad move hosing the engine down.


Did you cover anything at least???

[RoadShreader]

Yikes............. ok, ok. I made a mistake by cleaning the engine bay and hosing it off.

I'll pull the spark plug wires tomorrow and check all wiring in the engine compartment.

I vow not to spray water on the engine again.

Fantastic how fast I received replies to this post. Ten times better than email.

I'll continue to entertain thoughts for correction, gather the information, and may a go at it in the morning.

Thanks for the responses and not completely beating me up for a common mistake.


Steve.

[99M3Riverside]

I am holding all my grievences for Festivus tommorrow. www.happyfestivus.com

[Brandon318]

I don't think it was hosing the engine that caused this problem. Almost all of the connections are sealed in some way. I've sprayed this engine down many many times and have never had an issue. But then again, I know what not to spray and I also dry everything off immediately. If there was a bad connector that leaked water, then maybe you caused this, but most likely not.

And Badgtho, it was the pre-1996 E36s that are more susceptible to ECU flooding. In M.Y. 1995, BMW revised the firewall by adding a drainage passageway that funneled water away from the ECU. The info is in the BMW TIS; if you want, I can pull it up for you.