4 banger trouble-shoot ....

Posted By: dOrk !

4 banger trouble-shoot .... - 10/29/10 03:51 AM

90 caravan 2.5 ..... NO spark and no power to the fuel pump ... the pump checked fine on-the-bench.

I messed my hand up and I can't work on it.

NO codes to the best of my knowledge ..... ANY suggestions? (bad PU in the distrib?)

THX

Posted By: sreinheimer

Re: 4 banger trouble-shoot .... - 10/29/10 06:10 AM

Auto shutdown relay (ASD) i think can cause no spark and no fuel but not 100% on that

Posted By: dOrk !

Re: 4 banger trouble-shoot .... - 10/29/10 06:53 PM

THX ....I will have him check that. What is the purpose of that relay ?

Posted By: chache876

Re: 4 banger trouble-shoot .... - 10/29/10 07:05 PM

Quote:

THX ....I will have him check that. What is the purpose of that relay ?

It provides 12v to the fuel pumps, ignition coil, injectors, etc...

Basically so that it kills fuel pressure when the key is turned off to prevent fires, run on, etc...

Posted By: dOrk !

Re: 4 banger trouble-shoot .... - 10/29/10 07:15 PM

COOL ... sounds like that is the ticket ! My bud has the Haynes manual and the vehicle ...so I must ask ...WHERE is that relay in the car?

Posted By: chache876

Re: 4 banger trouble-shoot .... - 10/29/10 07:29 PM

I'm not 100% sure on that vehicle but they're usually on the firewall in a group of 3 relays. The haynes manual will tell you for sure.

Posted By: Dave_J

Re: 4 banger trouble-shoot .... - 10/30/10 02:31 AM

On the P-body cars, all three relays are between the battery and the brake booster. Its one of the three. The wiring diagram will show what wire colors to look for.

Posted By: C-Tech

Re: 4 banger trouble-shoot .... - 11/01/10 02:30 PM

The pick up coil is much more likley to be bad then the ASD relay, check for power to the coil on the + side when you first turn the key on should power up for 3 seconds if you have power there the ASD is working properly. the fuel pump and coil are powered by the ASD but the computer will not turn it on if it does not see a signal from the pick up coil while cranking.

Posted By: DaytonaTurbo

Re: 4 banger trouble-shoot .... - 11/01/10 06:23 PM

Quote:

The pick up coil is much more likley to be bad then the ASD relay, check for power to the coil on the + side when you first turn the key on should power up for 3 seconds if you have power there the ASD is working properly. the fuel pump and coil are powered by the ASD but the computer will not turn it on if it does not see a signal from the pick up coil while cranking.

Incorrect. The computer will prime the fuel pump even before you start cranking. When you put the key to the run(but not crank) position you should hear the fuel pump for a few seconds. The pickup fires off the injectors and you are right in that the fuel pump will not continue to run past the 3 second prime if there's no signal from the pickup in the distributor, but it will still prime when you turn the key to run. It will only try to prime a set amount of time per start cycle but I don't remember how many times that is. Maybe 5 or 6 times if memory serves.

The older years had the ASD relay built into the ECU but by 1990 it was a seperate relay. On the cars at least it's around the drivers side strut tower area. Not sure about the minivnas.

Posted By: Dave_J

Re: 4 banger trouble-shoot .... - 11/01/10 07:21 PM

But if it does prime the fuel rail for that 3 seconds, it will do it once untill the pressure bleads down.

If it does prime and crank over but will not start, pull the disrtibator cap and see if the "rotor" rotates while cranking. If not, broken Timing belt could be the cause. VERY COMMON! Unless its a highly modified 2.2/2.5 with a high CR and high lift cam, they are a NON interferance engine and all should be ok if the belt breaks.

Posted By: C-Tech

Re: 4 banger trouble-shoot .... - 11/03/10 05:47 PM

Quote:

Quote:

The pick up coil is much more likley to be bad then the ASD relay, check for power to the coil on the + side when you first turn the key on should power up for 3 seconds if you have power there the ASD is working properly. the fuel pump and coil are powered by the ASD but the computer will not turn it on if it does not see a signal from the pick up coil while cranking.

Incorrect. The computer will prime the fuel pump even before you start cranking. When you put the key to the run(but not crank) position you should hear the fuel pump for a few seconds. The pickup fires off the injectors and you are right in that the fuel pump will not continue to run past the 3 second prime if there's no signal from the pickup in the distributor, but it will still prime when you turn the key to run. It will only try to prime a set amount of time per start cycle but I don't remember how many times that is. Maybe 5 or 6 times if memory serves.

The older years had the ASD relay built into the ECU but by 1990 it was a seperate relay. On the cars at least it's around the drivers side strut tower area. Not sure about the minivnas.

Check you wiring schematics it primes the Fuel pump by cycling the ASD There is no separate wire to the fuel pump only the ASD that is why the coil is hot for those same 3 seconds. So I am not "Incorrect"

Posted By: therocks

Re: 4 banger trouble-shoot .... - 11/04/10 12:47 PM

Correct the ASD fires the pump for 3 seconds every time the key is turned on.Ive had a few also where the shutters under the pickup broke and didnt turn.You should be able to fell the relay click on when the key is turned on.As suggested check that the dist is turning as belts were a common problem with them.Ive even seen some that the teeth get torn off and they skip them catch then skip.They are easy cars to diag and work on.Also check the positive cable real close to make sure one of the wires hast broken.I also had one that a large ground on the rear of the head had broken and wouldnt start.Rocky

Posted By: dOrk !

Re: 4 banger trouble-shoot .... - 11/04/10 07:13 PM

THX guys ferr da input ... NO news yet ... he is working on lots of regular peoples cars in prep for the winter.

Oh ... it is NOT a belt failure. It does have compression ... you can hear-it in cranking. I have lost a 2.2 belt before ....I know how THAT sounds like during cranking

Posted By: C-Tech

Re: 4 banger trouble-shoot .... - 11/04/10 07:19 PM

Quote:

THX guys ferr da input ... NO news yet ... he is working on lots of regular peoples cars in prep for the winter.

Oh ... it is NOT a belt failure. It does have compression ... you can hear-it in cranking. I have lost a 2.2 belt before ....I know how THAT sounds like during cranking

I still lay odds on the pick up coil.

Posted By: dOrk !

Re: 4 banger trouble-shoot .... - 11/04/10 07:24 PM

THX C .... if you look at the first post ...this is what I thought also.

It is in his hands ... but I wish it was diff. This Caravan gets TWICE the fuel econ of my diesel dually with the truck camper(this was prepped for my FL excursion)

Posted By: C-Tech

Re: 4 banger trouble-shoot .... - 11/05/10 02:28 PM

Sent you a PM Doc