My Ti dies when I give it gas

[MattB318ti]

I have been racking my brain over this for a week. I was driving down the road the other day and as I gave it some gas to pass someone it just lost power completely. Then when I tried to accelerate it wouldn't go above 3k RPMs. Most everything is new on this car: Head, all sensors, vacuum hoses, fuel pump, fuel filter, entire coolant system including the radiator and water pump and thermostat and It has a 3 year old MAF sensor. Odd thing about the whole thing is that I haven't gotten any OBD2 Codes.

I have checked my fuel pressure which was around 37 to 40 PSI and I think 3.7 bar at the rail. My spark plugs are brand new and so are my ignition cables. I thought it could be the coil pack and I wasn't getting spark. I took the cables off and, one by one, verified that I had spark. When I try to start it I smell gas really strong in my exhaust. So I am getting fuel through the injectors and spark at the cylinders. Even weirder is that now, if the car even starts, when I give it gas the RPMs go up to about 2500 and the car just dies. After that the car won't start and the gas smell returns like the car is flooded.

I have taken the DME out of the car to make sure there wasn't water or anything else inside that looked like it could've gotten wet. I noticed there was a relay next to the DME that looked toasted. I replaced it and put everything back together and it didn't change a thing.

What I am really wanting to know is if someone has had this problem before and what they did to fix it other than what I have already done. Or does this sound like the DME has gone bad and won't maintain the timing? I am really at my witts end with this car. I have done nothing but work on it day after day to keep it running and at this point I am loosing patience. Please tell me anything you think would help me fix this issue. Thanks guys!

[Uber E30]

I had this exact issue before, but in an e30. No errors, car would run fine sub 3000 rpm but the second i went above that it felt like fuel pressure totally died. I believe the gas I had got some water in it because all i did to fix it was:

1. drain the tank
2. drive around sub 3k rpm till all the fuel was out of the lines
3. put new gas in
4. pulled the ECU and let it sit unplugged for 1+ hour

I hope that solves your problem, because its a cheap fix =D

[wodcutr]

When you rebuilt the motor did you get the fuel lines crossed? DME could also be in limp mode if the crank or cam sensor is not functioning, but you should get a code for that. What year is the car? The late m44s have a fuel pressure increase when you floor it and it is controlled by the DME...FPR is next to the filter under the car.

[MattB318ti]

I replaced the cam sensor a few months back and the engine rebuild was done years ago and the car has run like a champ since both of those repairs. It is a 97 m44. I do remember there being some little module with vacuum style hoses going to it next to the fuel filter when I changed it last. I did look in the fuel tank when I changed the pump to see if I saw any water and I didnt see anything. Doesn't mean the fuel isnt bad though and changing it out is another cheap thing to do. I didn't work on it today because we are moving this weekend. But I will get to it again sometime this weekend. If I am going to drain the fuel and replace it I should probably take the filter off and blow it out too in case any water is trapped inside right? Really appreciate the responses. I will update this as soon as I do some more work to it. :-)

[Uber E30]

I just siphoned my tank, got one of those little one gallon emergency containers and drove the car around the block till it sputtered out. Put the gas in, drove to my house, left the car parked with ECU in hand and watched some tv. Plugged it in an hour later (enough time for the ECU to reset out of limp mode) and was good to go.

[MattB318ti]

Ok so I put fresh fuel in with some STP gas treatment and a little booster to ensure that any water in the tank is dissipated. I have also taken the fuel filter off and I blew it out and put it back on. Now the car doesn't start at all. It cranks but doesn't turn over. I read that this could be crank sensor related. I have no cel codes. I am completely stumped now. What you think?

[wodcutr]

I wonder if you have two of your spark plug wires switched. Do you have them in the right firing order? You might want to verify your crank sensor too. Just because it has been replaced doesn't mean it isn't bad. Also check your temp sensor that goes to the DME. Test it to make sure it is sending the right ohms for the temp of the motor. Do you have a bentley manual? I would also clean the MAF or swap in a known good one to eliminate that.

[MattB318ti]

The cam sensor is new. I haven't touched the crank sensor yet. The maf is good, tested it in another car, also there isnt a problem with the firing order because the car ran fine for the past year since I changed the wires and plugs. Wrong firing order would have been apparent immediately. I have not checked the temp sensor. However would the temp sensor stop it from starting? I thought that only affected it in top end. Also I have no codes or lights on. So bad crank or temp should light up something on my dash. Crank is my next move. There is also the diverter. I doubt it is the diverter though since I have good pressure at my rail. I will repost once my crank sensor is changed. Thanks for all the help! I really need the extra ideas.

[Bobtail_Bimmer]

The guy I bought mine from stated that the only thing he ever had to replace was a sensor because his was doing the same that you described. I'm sorry but I couldnt tell you what its called or where its located but I do know that it had something to do with the cruise control. He never received a code either. Mine is a 95 M42 so not sure if you would have the sensor in question. Not sure why you wouldnt. Hopefully someone else will chime in and be able to tell you more.

[wodcutr]

I don't think a bad temp sensor would throw any codes. It would definitely effect being able to start the car because the DME will think the car is either really cold or already warm and this changes the enrichment of the air fuel mixture. I am leaning more toward the crank sensor though. Test it before you replace it. There is no need to throw parts at a car unless you know they are bad.

[MattB318ti]

I am really starting to think it is the crank sensor. I believe the m42 and m44 share the same sensors for crank and cam. I am going to check the ohms on it today and see if I am getting the correct number. If not then I will replace it. As far as the cruise control issue, i wonder if that is because of the sensor that controls throttle while cruise control is on. That would seem unlikely though since I would have to turn it on first. I will disconnect power to the cruise control and see what happens when I get home from work. Anything is worth a shot now. Thanks for the reply. I appreciate the help.

[MattB318ti]

Yeah I think you are right wodcutr. I am going to test it today. Like you said I would hate to throw another 100 bucks at it for no reason. But the car is 15 years old and running the original sensor. So the chances of it being bad are high.

[MattB318ti]

Ok so I checked the resistance of my crank sensor when I got home and it is reading on the 2k setting of my meter .605. That would be 605 ohms. Now what I can't figure out is if that is a bad number. What is the stagnate resistance for these sensors on this car?

[wodcutr]

The reading should be 1280 ohms across terminals 1 and 2. I think you found your problem! I would also suggest buying a bentley manual so you can fix your car yourself and not have so many problems figuring out stuff. It really is worth the money!

[Bobtail_Bimmer]

Run a search on the site. There is a free bently download available.