So I have posted before on my LR's starting woes. Here are the problems:

Symptoms were to replace the crank sensor, which I did. I have replaced all the spark plugs (and gapped them according to the specs on RAVE), for good measure I bought a new battery. I have spark, and I have the correct fuel pressure according to the RAVE manual as well. We have the correct fuel pressure within specs of manual.

I turn the engine on, and it seems like it wants to turn over but does not ignite and start.

What else could it be? Anyone else have a similar issue, and was able to fix it?

The only other thing that has not been checked is compression.

Thanks in advance.

Chris

 

Have you tried cranking while pushing the gas pedal open just a fraction, like clearing a flooded engine with a carburetor? If not, try it.

IACV and port clean? Check Engine Light on? Codes? This is a computer controlled vehicle, spark and gas aren't the only elements of the equation. The ECU stores codes, might want to purchase a reader for the tool box.

 

First, you never use the gas pedal to start a fuel injected engine, screws with the ECU.
I agree though, do you have codes, if so what are the fault code numbers?

 

Agreed but it would appear that the ECU is already screwed wouldn't you admit? If the engine is getting too much fuel (for reasons we do not yet know) it will allow enough air in to get it to start. Besides, if you hold the pedal once it starts to just above 1k the ECU will eventually hold the idle after a minute. I preach what I practice. It's started mine a time or two with a bad coolant temp sensor before replacement. If everything was up to par then holding the pedal would be a problem on a fuel injected motor. Just a suggestion, use at your own risk (not much of one in this case). Good knowledge gets those out of the field and back to the garage, wouldn't you agree Mike?

Good luck.

 

If MAF is unplugged, engine will try to start and die before it reaches idle.

If coolant temp or incoming air temp sensor are unplugged they use default values.

If TPS is fried it it will start but go high, like 1700-1800 rpm

If Crank sensor was bad, no spark

If cam shaft sensor unplugged ECU will use "standard" timing as a default

But like Mike says, most of these make a code and the light to be on (if light works or was not painted over by previous owner - code readers show the "MIL status" for the light to be on). Now how to drag the dead truck to a parts store for a free code read is a different story.

 

Sorry for the delay in response, live in Hawaii, and just woke up. Yeah, I bought a code reader already. No codes. I will try to do it again and see if I come up with a different answer, didn't check the codes after the cranksensor switch last night.

 

What IHScouts is saying is that if the idle air control valve is bad and you hold the throttle part way open it will allow air into the engine, which is what the IACV does and if the IACV is not working and thats why the engine will not start, holding the gas pedal 1/4 of the way down while starting the engine will give you a idea if it is bad or not.
SOOOOO, hold the gas pedal part way down, if the engine starts replace the IACV, if the engine does NOT start keep looking.

At idle the throttle body is closed, the IACV opens and allows enough air into the engine so it can idle.
Open throttle and it closes.

 

Thanks Spike! That's what I'm saying.....We have fuel and spark....what's missing, the idle circuit.

 

No problem friend, I knew what you were trying to say.

 

Any results yet?

Beginning just yesterday, I'm suddenly having the same issue with my '97 (87,000 mi.). Won't start or idle most of the time if I don't press the throttle a little. Starts and runs if I depress the throttle a little... and I can keep it running if I feather the throttle lightly.... But dies if I leave off the throttle completely.

The first thing I always check is the connectors. I just don't trust them and have cleared up problems before, simply by unconnecting, cleaning and reconnecting various sensor and actuator wire connectors.

I just bought a tester and checked fuel pressure (37 lbs at key on, 30 lbs when running at idle, drops to 25-27 at around 1500-2000 rpm and goes no lower than that). I have a new fuel pump in the vehicle anyway.

I'm thinking IAC. Removed it, cleaned it.... Didn't need it, it was cleaned fairly recently and still seems fine. But when I removed it after driving a short distance (feathering the throttle to keep going), the body of the IAC seemed warm... Might be my imagination, but seemed warmer than the engine as a whole.

While at the parts store I picked up some MAF sensor cleaner. I'll give it a cleaning once it's cool, but I really didn't think it was that, anyway. Previously I've had what seemed to be fuel starvation symptoms (lack of power, intermittent missing, especially under load) at freeway speeds due to the MAF, but I don't recall bad starting/idling problems like these. In the past cleaning it worked fine and I'm really hoping it's not the MAF, the damn things are so expensive and hard to get (local parts store wants $800+ to send it in for a rebuild, days of the car sitting waiting for it to be returned, and then there is no warranty)!

I was going to wait for the engine to cool down to check the crankshaft sensor and it's connectors... but if that would kill spark, I'm not having any problems with that.

So I'm seriously considering ordering an IAC and see if that fixes it. It's a one-day order item and not too pricey... But I seem to recall some Jeep or other uses the same part... Anyone know?

P.S. Forgot to mention... no Check Engine light warning at all. And, yes, I checked with code reader and there are no faults registered (except for a persistent "rough road" fault that shows up every now and then... it's a bad ABS sensor I've been told, but I have ABS disabled and simply clear the code every month or two when it turns on the Check light).