tomcat

Happy Memorial Day to all Vets!

I was driving along, in traffic, on a ramp a few weeks ago and I realized my realized I could not accelerate. Engine still sounded ok (i.e., still firing), but was slowly decelerating. I was able to get a momentary accel, but finally pulled over on the shoulder and towed home.

On the shoulder and at home could not start. Starter, but no fire.

For the previous 6 months idle was a prob. Sometimes high and would stall during the first couple of minutes if I took my foot off the accel. But after a few minutes, everything seemed to be fine (e.g., stop light). Weird thing is if I stopped after my drive and started again a few minutes later, same problem with unstable idle and stalling. Speedometer and tach would not work for the first few minutes sometimes also.

The last week I have replaced all "53" relays and JHowell checked out my MAF, EZK, and LH - all seem to be ok. TPS is clicking, got spark on both banks, fuel pump is running. Also, when I started with the "ends" on the "log" intake off, I saw white smoke which I assume is fuel.

When I try to start now (The first time between battery charges), it seems to fire for a second or two, but does not completely start. Then when I crank, no fire. Then, charge the battery, crank, fires for a second, then nothing. Tach does not move when starting.

I have not checked fuel pressure and am considering replacing the CPS. Any other suggestions?

Mike Frye

Hey John,

How's it going?

How about fuel injectors? Maybe an intermittent short or broken wire? Do you have a meter or 'noid' light to check for voltage while cranking?

You may be on the right track with the CPS, and if it is the CPS you probably won't have injectors firing either, but if there's a break or a short in the harness somewhere you'll get nothing anywhere because the injectors 'batch fire' all at once.

tomcat

Hey Mike.

Definitely read about the shorting problem in the fi wiring - really hoping this not the case.

I think some old posts (Stan) say if the CPS is not working you shouldn't get spark, which I am. Pretty confusing.

I think I am going to check my grounds, except I have no idea where these are - well at least the ones I want to check.

Landseer - if you read this post, where is that grounding point for the computers? Pass side near the bell housing. Can't see it.

There was another post for a ground point on the pass side off of the cam tower cover. On the body or engine?

Tampa 928s

Try unplugging your Maf see if it starts. Did you work on the car recently?

tomcat

Tried starting with the maf unpluged - no helpy.

Timing belt less than a year ago - uneventful except I forgot to place the copper arm for the tension warning.

Been running great except for the recent unstable idle - just assumed it was the isv. In fact, all of the suspect connectors look good (temp II, CPS, TPS).

tomcat

I've reading the old no start posts. What is a little confusing is what triggers what in the starting process.

I think noid light to check injectors and then fuel pressure. Would I be correct in saying no one knows what a bad cps looks like (i.e., no definite symptoms)

Tampa 928s

If you have access to a scope you can see if it is working. The cps signal must be present for it to start. Unless you have a hugh vacuum leak which could be from the intake boots check your cps.

tomcat

Not true that spark means CPS is ok?

Another question. Is the original fuel from some start up injector? Something I read, but not sure I believe it - maybe for the 4.7s?

docmirror

Sounds like ignition switch to me.

Tampa 928s

You need to start from the beginning since you said car had idle issues and loss of power do not discount your boots leaking, smoke test the intake.
You have spark verified by a timing light?
You have fuel verified by FP running but have not tested for pressure?
You need to get a noid light you can test the rear passenger injector it is the easier one to get at.
Switch is a possibility but step by step testing following the WS manual procedure is the direction I would take.

Mike Frye

I'm going to lean away from the CPS since it was running rough. I feel like if it was going it would give you stall/no start as a warning (if there was any warning) not rough running.

Has this car been through the top-end refresh and fuel line replacement?

What is your cranking voltage on the battery? You said you tested a few times then had to charge the battery. A weak battery will do really weird things and if compounded with something else like weak grounds or injectors grounding it could be the last nail in the coffin.

tomcat

Spark test with a spark plug wire on each bank. Fuel tested by seeing fuel come out of the fuel rail (bolt cracked open) while starting - pressure was not checked. No smoke test - I cranked while having the intake end caps/"oil reservoir" off. White smoke I assume is fuel mixture. In hind site probably not very smart.

Rough idle, but only at start up. No top end refresh and lost the pass side vent hose from cam tower cover (disintegrated years ago). Have not isolated the screwy idle to vacuum leak or bad ISV. That "U" fuel line looks perfectly good.

Thought bad battery/alternator. Charges to 13+. One-man show for the last couple of weeks so have not been able to do the two-person stuff. Videoed the spark while cranking. Hoping this would be simple. Not simple.

CPS is ordered. Worse case I will have a spare - if I don't break it. Do not know what the prior history is, but all sensor connectors look good (i.e., seems many times sensor problems come from the connectors fall apart). I know, not a great assumption.

I would like to check the grounding points for the ECUs. No clue where they are. Bell housing? End of block? Seen from the top?

SteveG

New Visitor thread, post 33. May not answer your specific question, but it is a start.

tomcat

Thanks Steve. I was using those diagrams to locate the ground I am looking for. I believe passenger side rear block, but could not find it.

Mike Frye

John,

Remove the air filter box and the MAF. Put a rag in the lower air guide where the MAF used to be so stuff doesn't fall in there.

Now you should be able to see the grounds on top of the rear of the engine near the bell housing. With battery disconnected, remove and clean each of the wire connections you find there before putting them back on.

I'm going to go on record as saying you're due for a top-end refresh and fuel line replacement. Just because the line looks good doesn't mean it's good inside and that's not a surprise anyone wants to see.

I remember your car and I know it was low mileage when you got it, but I think age is as much a factor as heat cycles in this case.

You will also be able to isolate and fix any vacuum leaks at the same time.

True, it's not really a method of fixing a no-start condition but it will ensure that all of the connections and common failure points are dealt with.