First High Idle And Now Won't Start

[aurealeus]

I have owned my 1995 Mark Vlll for almost ten years and it has always started with one short turn of the key.

The day after a severe thunder/electrical storm, I started my car as usual but noticed that the engine was running at a very high idle and had to brake most of the time while driving. Thinking that something must have got wet from the storm the night before, I drove it approx five miles while idling high assuming it would eventually dry out with the idle returning to normal. About an hour later when I re-started the engine, the problem returned. I then made a second stop and re-start and had the same high-idle problem. I drove a few blocks to do another errand and when I attempted to start the engine a third time, it cranked but would not start.

After trying to start for a while, I disconnected the battery cable for a few minutes to re-set the computer and the engine started without any problem, this time with my usual normal idle. I then drove approx another two miles and the high idle returned so I pulled over and shut the key off. Since then, the engine will not start. Starter cranks without effort but will not turn over. Fuel pump starts when key is turned. Also tried resetting the pump switch in the trunk numerous times to no avail.

Any advice or suggestions what I might look for or try to self-diagnose??

Thank you in advance for any help you might offer.

 

[maxmk8]

Probably 2 problems.

1. Crank Sensor is causing your non start condition. Wiggle it around... it is right in front of the ac compressor, car should start.

2. High idle is caused by a bad idle air control valve... a big pain to get to on gen 1 mark VIIIs. It is located in the back of the intakemanifold towards the firewall.

 

[Misanthropy]

Here is your idle air control valve and gasket. I couldn't get to 1 of the bolts with a universal, flex, short extension, or just closed end ratchet. I had the windshield housing removed and I removed the plastic curve that holds the fuel lines together from the top. You can see in picture #3 it is to the left(correct terminology would be to the right) of the throttle body.

 

[J]

Probably 2 problems.

1. Crank Sensor is causing your non start condition. Wiggle it around... it is right in front of the ac compressor, car should start.

2. High idle is caused by a bad idle air control valve... a big pain to get to on gen 1 mark VIIIs. It is located in the back of the intakemanifold towards the firewall.

1. DO NOT wiggle!!!!!! Unplug it and plug it back in a couple of time, this will clean the pins. Wiggling it will disconnect the internal connection! (Come on Max!)

2. +1 stuck IAC Valve

 

[maxmk8]

1. DO NOT wiggle!!!!!! Unplug it and plug it back in a couple of time, this will clean the pins. Wiggling it will disconnect the internal connection! (Come on Max!)

2. +1 stuck IAC Valve

I wiggled mine gently 2x and it solved my non start conditions... what is the point of disconnecting it?

 

[aurealeus]

Thank you everyone. I will try all of your suggestions.

Misanthropy, thank you for providing the pics. I hope
that you already had them on hand and didn't go
through the trouble of disassembling on an actual
vehicle just to show me.

Anybody got any ideas regarding my "no-start" problem?
The no-start and high idle happened simultaneously as
described in my original post after a severe lightning
storm that was in very close proximity to the car.

You guys are great and this novice truly appreciates
your suggestions.

 

[budpytko]

See Post #4 for your no start

 

[J]

Did you try giving it a slight amount of throttle? If you Idle Control Valve is completely stuck shut, the car will NOT start unless you provide a bit of air by opening the throttle. You'll have to control the idle with your foot.

 

[aurealeus]

Thanks again for your imput. I haven't tried anything with the car in over a month but have plans to try again today with a friend who is a mechanic and has previously owned a Mark Vll and understands more about the Mark Vlll "rocket-ship" engine than I do.

By the way Jesse, checked out your ride and your Mark looks almost exactly like mine before your conversions except that I have the tan interior. (not to mention some body damage from a rear-ender that I hope to also repair one day) I'm the second owner with a Lo 84000mi. Bought it in 1999 with 37000

I'll let you guys know how I make out after trying out your suggestions today.

 

[J]

Nothing wrong with a Silverfrost Gen 1 Tan interior....I don't think I've ever seen one with Tan! You'll have to post up some pics when you get her going again!

 

[aurealeus]

Well.... got it started yesterday. Jumped my drained battery and sprayed starter fluid into the air intake close to the IAC and it started right up which I assume rules out any electrical problem regarding the no-start. Then went to AutoZone and replaced my old four year old 650 battery that was on its way out with a new 750 and then tried again. Much better cranking now but still wouldn't start without another shot of starter fluid.

Started and stopped the engine three additional times and each time it required a shot of starting fluid to start the engine... but did start each time without much effort. Poured some Lucas injector cleaner into the gas tank and let the engine idle for about twenty minutes or so and drove it up and down the street a short distance but the engine is still idling high at around 16-1700 RPM and "bangs" into gear when shifting. Normal idle for my car has always been somewhere around 5-700 RPM.

After letting the car "high-idle" for that time, I shut it off and again tried to restart one more time without a blast of starting fluid with no success. By that time it was becoming late and I had errands to do.

Due to my limited time yesterday, I avoided removing the plastic intake that is attached to the IAC at this point to clean it thorougly since it appears to be a hassle to do requiring a square 90 degree allen type tool and removing the windshield housing for clearance. I will have to clean it over this weekend when I have more time.

Hopefully this latest update provides a better indication of what might be going on with the engine now that we know it will start and stay running albiet the continued high-idle.

I appreciate any suggestions how I might proceed from this point.

Thank you.......

 

[driller]

CAM SENSOR!

The likely explanation is the starting fluid {cringe} allowed the car to start. The cam sensor controls fuel injection timing. Once started and running however, the car will run without a cam sensor signal!

The cam sensor is located behind the power steering reservoir in the front of the drivers side head.

The intake tube retaining bolt requires a 1/4" square drive ratchet for removal.

Still, the high idle is likely the IACV.