Author Topic: New Car: BIG cold start problems (Read 27416 times)

fiftytakedowns · « **Reply #75 on:** January 10, 2010, 11:51:10 PM »

I have the e36 bentley and its very very vague it just sais the values to test for

fiftytakedowns · « **Reply #76 on:** January 25, 2010, 06:40:31 PM »

I dont want to dump money into sensor or anything else to figure out this cold start problem.
it's hard to do the testing without the proper materials at my place at school so I decided that I'm going for an M50 swap When the summer comes, ill be acqumulating parts and other materials to get that ready, until I can do the swap at my boss's shop.

Thanks everyone for the help, It's too bad I could never figure this out.

dinu.negrean · « **Reply #77 on:** February 21, 2010, 03:50:28 PM »

I see that you have abandoned the fight. But if you're still thinking of it you can really eliminate the O2 sensor from your list. The computer will ignore it until it reaches the working temperature ~5min.

I own an m42 E36. I have two temperature sensors on the engine, the first one sends the signal to the computer, and the second one to the gauge. You may want to try to replace the one sending the signal to the computer. It is not expensive and it is worh trying.

From what I have seen it behaves almost like it does not know the TB is open. You may wanna insist on that TPS.

I'll think about it anyway, maybe i'll come up with something.

jeff_b · « **Reply #78 on:** February 22, 2010, 07:33:11 AM »

Quote from: dinu.negrean;88043

I see that you have abandoned the fight. But if you're still thinking of it you can really eliminate the O2 sensor from your list. The computer will ignore it until it reaches the working temperature ~5min.

I own an m42 E36. I have two temperature sensors on the engine, the first one sends the signal to the computer, and the second one to the gauge. You may want to try to replace the one sending the signal to the computer. It is not expensive and it is worh trying.

From what I have seen it behaves almost like it does not know the TB is open. You may wanna insist on that TPS.

I'll think about it anyway, maybe i'll come up with something.

^This.. Replace the DME temp sensor....

fiftytakedowns · « **Reply #79 on:** April 10, 2010, 01:33:03 PM »

Arent the coolant temperature sensor, and the DME temperature sensor the same thing?

I also replaced the 02 sensor, getting bertter mileage, but didnt fix problems.

I also got a narrowband AFR gauge. Ill let you know how it acts when the car actus funny.

It does go from lean to rich pretty openly on idle.

Ryann · « **Reply #80 on:** April 10, 2010, 02:44:17 PM »

Run the car in it's non-drivable state and shut it off before it begins to run normally, then pull out the spark plugs and tell us what you see.
Also, have you verified the quality of your battery connections?

fiftytakedowns · « **Reply #81 on:** April 10, 2010, 06:59:36 PM »

The AFR gauge was telling me that as it was bogging it IS getting fuel. so Now I can narrow it down to spark. which pretty much points directly to a crank position sensor.

jeff_b · « **Reply #82 on:** April 28, 2010, 09:26:16 AM »

The coolant gauge and the DME sender are two different units, tan and blue screwed into the head below the lower intake. The forward blue unit is for DME. The sensors are an NTC (negative temperature coefficient) type, meaning as the temperature increases, electrical resistance of the sensor decreases. The control unit reads the voltage change in the circuit as temperature.

About the CPS, I thought if the crank sensor shit the bed, it won't run at all........isn't it one of the first things the DME needs to be satisfied to tell the fuel pump to turn on?

fiftytakedowns · « **Reply #83 on:** April 29, 2010, 02:48:03 AM »

I replace the BLUE DME coolant temperature sensor. I remember putting in a resistor in the plug of the value of what it would see if it was "warm". It worked half of the time.

Im thinking that maybe when cold something is not working like it should, or there is some problem. I finally know how to use a multimeter, and have a basic understanding of wiring, I just dont know where to start testing. I have prett much tested every sensor.

only one hta seemed fishy was the cps which was like 30 ohms under spec, and the TPS which was sending a varable change in voltage of 2-5V from when it was closed- open.

thanks!

jeff_b · « **Reply #84 on:** April 29, 2010, 06:56:54 AM »

Did you test the ICV this way?

1.   Unplug the idle speed control valve connector and check for 12 volts at terminal 2 with the ignition switch ON. Power comes from terminal 87 of the main DME relay.
2.   To check the motor resistance, connect an ohmmeter to terminals 2 and 3 of the actuator. It should read about 20 ohms. Terminals 2 and 1 should also read 20 ohms. Resistance across terminals 1 and 3 should be about 40 ohms. The terminal numbers will be imprinted on the connector body with terminal 2 in the middle position. Terminals 1 and 3 are the outer terminals and the exact positions are not critical to this test.
3.   If voltage and resistance readings are correct, remove the actuator and use a tool to carefully push the rotary valve sideways to the fully open position. With the wiring connected and the ignition switch ON, the valve should move to about the 50 percent position and remain stable.

fiftytakedowns · « **Reply #85 on:** April 30, 2010, 02:20:32 AM »

Im almost positive the ICV is working, its buzzing, I have spares, which also all work, they have all been cleaned etc. When I blip the throttle the Door Moves, I think it goes shut Im pretty sure, Id ont remember, but I had one on the car, and the plug on a separate ICV to see how it reacted, which seemed positive.

jeff_b · « **Reply #86 on:** April 30, 2010, 08:06:16 AM »

Quote from: DesktopDave;84378

The sensor can be tested, let me see if I can find that somewhere. I should really print up a copy of the manual to have on hand for reference.

I'll bet the thermistor can be replaced too, likely it's a $5 part at DigiKey or a domestic cross-ref exists. I'd like to remove mine...it's right in the middle of the airflow into the engine & I'll bet it impedes flow.

On M42 engines, the air temperature sensor is inside the housing and must be tested as part of the air flow meter circuit. I have a .pdf version of the M42 emissions diagram if you need it. I'm not sure of the resistive range values the vane will display, but whatever it is, the resistance should increase/decrease smoothly, with no shorts or opens.

PumpItUp · « **Reply #87 on:** April 30, 2010, 05:07:51 PM »

did you ever try to run the car without a cat? because its screaming clogged cat. and if that's too much work, did you at least try seafoam yet?

fiftytakedowns · « **Reply #88 on:** May 01, 2010, 09:18:24 PM »

I replaced the cat this summer. Not to mention, previously the car had a gutted cat, I thought it was a gutted cat as well. What values should i look for?

locknload · « **Reply #89 on:** May 02, 2010, 02:20:28 PM »

What about the wiring between the temp sensor and the DME, or wherever it goes? I'm just throwing this out, but perhaps it's the wiring? Should be pretty simple to trace the temp sensor wires (or look at a wiring diagram) and either make some jumpers or test them with your MM.

Also, have you checked/replaced the temp sensor on the top right side of the radiator?