| Author |
Message |
    
Glenn Guinto (Glenn)
| | Posted on Monday, April 29, 2002 - 04:17 pm: | 
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Hey there Rangie folks. I'm posting this for a good friend (John C.) who's going nuts right now trying to troubleshoot the idling problems of his 88RR.
This is copied and paste from his original email.
Problem starting: takes three to four LONG cranks before the engine starts. With a wire going directly to fuel pump it starts faster but still has problem idling.
Sometimes it will start and idle at 1,500 rpms and sometimes at 600 rpms.
When I shift into R or D it will drop to 200 rpms and stutter. If I try accelerating it will die. What happens when you put shifter in R or D? Why would the rpms go down so much?
Removed fuel pump (replaced with new one last summer) and noticed that one of the wires going into the tank was melting/burning the inside plastic connector: I had this problem with my old pump (check out pics of old pump here).
If I accelerate quickly it will stall.
Took it to a mechanic and he replaced a few vacuum hoses but could not determine exactly what the problem is. He recommended replacing the ECU (which did not work).
Replaced with new parts:
Amplifier (ignition module)
Amplifier relocation kit
Wires (magnecor)
Temp Sensor (ECTS)
Oxygen Sensors
ECU (used)
Distibutor Base Plate
Head gaskets replaced in early Feb, cleaned all parts thoroughly.
Swapped parts from George�s 89 RR:
Stepper motor (ran a little better) but my Stepper Motor runs fine on George�s RR
Distributor cap (mine was cracked, ordered new original LR and should be here by Tuesday)
Temp Sensor (no difference)
MAF (no difference)
TPS (no difference, also checked with multimeter: all tests OK)
Played with Idle Air Mixture
Switched Fuel Pump Relay with Main relay (no difference)
Removed cats: right side was empty except for a piece of honeycomb the size of a matchbox (black) the left side had some broken pieces and I gutted it (white). The middle cat was gutted out sometime last summer. No difference except louder.
I don�t want to keep throwing new parts on unless I am sure it will fix the problem. I�ve already spent close to a grand.
Anyone who can help, please post here or email John or me. Thanks!
-glenn |
doug james (Dgj95lwb)
| | Posted on Monday, April 29, 2002 - 11:21 pm: |
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What is your fuel pressure at the rail ? When was the fuel filter last replaced ? Low fuel pump pressure might indicate this symptom, arising from filter restriction.
Is the jet orifice for the stepper motor clean ?
I would confirm absence of vacuum leaks, using carb cleaner/starting fluid, directed, while idling, at all gasket joins and vac line ends. Just to double check that....
Fuel press regulator-swap that ?
Coil is fine, right? (swapped)
Swap out alternator:suspect but as a wild card, really. It is involved in many idle issues, accompanied w/fluctuating idle...
Apart from that, this is a TOUGH one !
Let us know in this thread when it's solved.
cheers, doug james |
Glenn Guinto (Glenn)
| | Posted on Tuesday, April 30, 2002 - 10:15 am: |
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Doug,
Thanks for your reply. I haven't talked to John yet but I'm sure he'll give your suggestions a shot. This situation is indeed a tough one. A mechanic already gave up on this truck. We will post any progress in this thread. Thanks again!
Glenn |
PerroneFord
| | Posted on Tuesday, April 30, 2002 - 10:47 am: |
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Doug,
How does the alternator play a role in an idle problem? I thought I understood automotive charging systems and then you throw out a curve. I mean, most alterators don't begin charging up the battery until they are spinning at over 1000-1500 rpm. Some people fit undersized pulleys to allow them to spin faster at lower engine rpm but I don't think Rover has done that have they?
-P |
Randall Smith
| | Posted on Tuesday, April 30, 2002 - 11:50 am: |
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Here are some items to check before you buy anything else:
I would first check for vacuum leaks using carb cleaner. Then I would check the fuel pressure, especially since you have installed a pump made for another vehicle.
I would then set the base idle speed. This should prevent the engine from stalling when something like this is causing the ECU not to be able to control the idle speed. I would check the road speed sensor which tells the ECU if you are moving or idling. Also check the park/neutral switch which tells the ECU what kind of load to expect.
Randall |
doug james (Dgj95lwb)
| | Posted on Wednesday, May 01, 2002 - 08:57 pm: |
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P:
You may be, totally right, on the alt comment. I was grasping on this prob as described, and it seemed to be the only part not yet replaced !
I am glad I haven't had any alt issues myself, in my RR. But ....in my last XJ6, the alt did fail @ 180k, but that was expected by the battery probs associated with its' impending demise. |
PerroneFord
| | Posted on Wednesday, May 01, 2002 - 10:01 pm: |
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I may be off base but here is how I see the problem.
To run the engine you need three primary components to come together under compression:
Fuel
Spark
Air
We are assuming that compression is good because the motor runs fine most of the time. A shift of the tranny adds load to the motor but wouldn't show up a compression issue necssarily.
Air. This can be diagnosed by running without the air filter and by making sure the air meter is good. Swap with a known good unit to test. Putting the car into gear would not suddenly cause RPMs to drop if airflow was the problem.
Fuel. If we assume fuel is the issue, we'd see problems at half to full throttle. Not problems at idle. Also, changing into and out of gear wouldn't cause a problem.
Spark. This is always troublesome. A change in load on the motor will always show up spark or ignition issues. Whether they be in advance curve, vacuum leaks, or a weak battery. If the charging system is weak, putting a load on the motor could cause stumbling.
How I'd troubleshoot:
I'd start with the charging system including the battery. Methodically swap all the parts looking for improvement. From there, I'd do plugs (you didn't mention those) wires, cap, rotor, coil, and finally the entire distributor. Check your timing both at idle and at RPM. Check for a sticky mechanical advance which might account for the stumbling sometimes and high idling at other times.
If the problem is not there, I'd check for fuel pressure on the rail both with a cold motor and hot, and at idle and under load. Look for leaky injectors flooding a cylinder or two. Look for misfiring injectors which would cause certain cylinders to run lean and shoot EGT up. Remember on a cold motor, the vehicle is running full rich as the o2 sensors are not yet providing signal to the ECU and metering the mixture.
Anyway, that's how I would approach the problem. You may want to buy 5 or 10 sets of plugs and use them for troubleshooting. It's a lot easier to read what's happening per cylinder by examining plugs. They are a great source of info. Put a set in a good running truck running the same fuel to get a baseline.
-P |
doug james (Dgj95lwb)
| | Posted on Friday, May 03, 2002 - 02:55 pm: |
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I too, am a fan of plugs as a diagnosis tool. Here's the process that works for me and may give others info:
Do a plug-cut, anyway, that's what we called it. Drive at freeway speeds, 70-80 for 15 mins, then turn off engine-'cut'- and coast to the side of the road. Do this when/where light traffic only. Pay attention that you DO NOT LOCK the steering. Important to cut the engine when at high throttle position/speed. Raise bonnet, and remove plugs, noting the burn characteristics. Helpful in locating the rich/lean jets in your triple Weber 45DCOE, or on your vintage Ferrari/Maser. Useful for all engines really. cheers, dgj |
PerroneFord
| | Posted on Saturday, May 04, 2002 - 06:41 pm: |
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Doug,
Do you have a spark plug magnifying glass? It's pretty hard to see some things without one.
-P |
John C.
| | Posted on Monday, May 06, 2002 - 09:05 am: |
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Problem resolved:
I feel like an a$$. It was the Rotor (ignition). It had a small hair line crack which I could only see with a magnifying glass. I assumed the rotor was ok because I had just replaced it in August. Stupid me.
The mechanic did also fix the advance timing mechanism; it was not moving. He also put in a new coil.
I was very surprised that the cap and the rotor only lasted 9 months (purchased from AB) specially since I take pretty good care of my engine.
Oh well, I've got an almost new Rover!!! It runs great (even for a 3.5).
Thanks everyone! Special thanks to Glenn for posting this msg, Stephan for picking up and driving my wife to work, Adrian for doing the same and letting me try some of his parts, and George who spent a whole day trying to help me. |
Glenn Guinto (Glenn)
| | Posted on Monday, May 06, 2002 - 03:13 pm: |
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Hey John...that was nice to hear that your Rover is back in action! Now let's go wheeling!
-glenn |
John C.
| | Posted on Monday, May 06, 2002 - 03:33 pm: |
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Soon, very soon. BTW Adrian has a new place in NJ...but shhh...it's a secret!!!! |
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