Idle problems and won't restart after stall
 

Hi,

I've been having an on-going battle with my 1990 2.3L normally-aspirated 100.

The first symptom was a low idle when engine warm. After about 15 minutes of driving, engine would try to idle around 400 and subsequently stall at every stopsign. Tried cleaning out the ISV...no change.

Noticed that the Multi-Function T Sensor wasn't working (dash gauge showing 0) so I replaced that. The dash gauge now works.

Now, the low idle still happens (but rarely) but a new symptom has been added... when cold, the engine surges, idle going up and down for the first 5 min of driving.

3rd symptom--and this is the most frustrating--if the car is warmed up, and I forget to hold the revs up manually while at a stoplight... it may stall, and once it does it absolutely WILL NOT start unless I let it sit for about 15 minutes. It cranks, but seems to not want to catch. After 15 minutes of not trying, I can start it with little difficulty at all.

The funky idle problems / occaisional surging might point to a defective ISV... but this last thing--not being able to restart after a stall...I just don't get it.

Anyone have any ideas?

(thanks in advance)

RE: Idle problems and won't restart after stall
 

MAF sensor

RE: Idle problems and won't restart after stall
 

also check the seal on the dip stick it effects pressure loss in the engine hence loss of idle or start up.


[IMG]local://upfiles/12092/F7420AC7604746689E50DC2CA73EF98B.jpg[/IMG]

RE: Idle problems and won't restart after stall
 

I think that you have a big vacuum leak somewhere! I had a similar problem on my 1991 100Q a hard start and idle so low that I had to keep my foot on the gas and brake when stoped! When I checked under the hood I found not one, not two, but three hoses that have worked loose. Check for loose hoses, bellows between the mass air flow sensor and manifold, especially pay attention to the plastic/nylon hoses they have a tendency to break. Rubber ones just disintegrate and if you still have any covered with cloth get rid of them.

RE: Idle problems and won't restart after stall
 

Thanks for the ideas... I haven't seen any obvious leaking hoses, but I'll have to do a little more hunting around. If it were a vacuum leak, wouldn't it be more consistent though? The low idle condition only happens when the engine is warm, and even then not everyday. Last night when I was driving the idle was consistently hight at around 1200. This morning it was surging up and down.

Left foot braking does get tiring sometimes, lol.

Can anyone describe where the MAF sensor is on this engine? I couldn't seem to find it in the book i have (my book is actually for a 5K, but much of the stuff is the same).

RE: Idle problems and won't restart after stall
 

VAF sensor on your car sorry mate

[IMG]local://upfiles/12092/6AF95749113E437E82831534D706488A.jpg[/IMG]

[IMG]local://upfiles/12092/2EEB8563567A42488B76E273EB237E53.jpg[/IMG]

RE: Idle problems and won't restart after stall
 

don't know if you can read that, if not I could use macro to take a picture

RE: Idle problems and won't restart after stall
 

just thought to try macro out


[IMG]local://upfiles/12092/F5801F00F35A4647AA5C2A56D3F9BDDC.jpg[/IMG]

[IMG]local://upfiles/12092/2336F70CB98144E2AC77BB0D91DB41AC.jpg[/IMG]

RE: Idle problems and won't restart after stall
 

mucho better im getting there, new to camera;)

RE: Idle problems and won't restart after stall
 

Interesting looking manual doesn’t look anything like my US R. Bentley!