'96 Intrepid no-start

My neighbor is having car problems. His mechanic told him to scrap it or
blow over a grand on it. Pfft I say...

It's a '96 Intrepid, 3.5L. From what I understand it was running great. One
morning the son went to start it and it just sat there cranking, and hasn't
fired since. I'm told his mechanic checked for spark and it sparks only one
time while cranking, although I haven't checked this for myself yet. From my
own quick once-over I do NOT hear the fuel pump and see no pressure at the
fuel rail after trying to prime it a few times or while cranking. So, are
there any common areas I should check? On this car, if the fuel pump went
out (swapping relays didn't help) would that kill the ignition system? Or
vice-versa? Does this thing have a crank or cam position sensor? I don't see
how that would stop the pump but this is the first I've looked into this
car. ECM? I can't imagine that there's terribly much wrong with it.

 

A short to ground in the fuel pump circuit -could- kill the
primary voltage to the ignition coils

The PCM needs to see the correct crankshaft and camshaft sensor
pulses in order to turn on the fuel pump and activate the
ignition coils.

Yes, both. Cam sensor is up top at the drivers side timing belt
area (reads off of the left cam sprocket), crank sensor is a the
lower passenger side of the bell housing (reads off of the
flywheel.

Doubt that it's the PCM.

First thing to verify is proper cam to crank timing.
If the cam sensor signal is not in correct synch with the
crankshaft sensor signal, the system is smart enough to kill
everything mentioned and you'll have the exact symptoms described.

Ask 'em how long it's been since the timing belt and water pump
have been replaced.

 

Borrow a Code reader from AutoZone, plug it in and tell me the codes.
Sounds like a cam sensor to me, though, & they're fairly easy to change. I
have a 94 Intrepede with a 3.3.

 

That is classic symptoms of a slipped timing gear or belt.

Ted

 

Crap, can't see the replies through my newsreader. I'm the OP though.

Well the obvious question is how do I verify the crank/cam timing? I'm
not the least bit familiar with the 3.5L... yet. Are there reference
marks on the pullies I should check?

I don't think he's had the car for more than a few months so I don't
expect an answer for that one I'm afraid.

 

Borrow a Code reader from AutoZone, plug it in and tell me the codes.

That reminds me, does the ignition on-off-on-off-on trick work on a
'96, like it does on my older Voyager and GCL?

 

You can test electronically with a 2 channel lab scope, this
method will prove or disprove whether the 2 sensors are in synch
but will not verify actual cam timing.
Alternately, you can remove the timing belt cover(s), line up the
timing marks (crank and both cams) and verify that way. This
looks and sounds worse than it actually is... I can do it in
about 20 minutes.

And it wasn't a consideration during the purchase?

 

As you can probably guess, you really need fuel pressure, and you really
need 3 sparks each revolution. Just keep looking until you're sure you've
got one and not the other.

Fuel pressure should come up before you start it. Every car is like that.
When you turn the switch on it should run. If it doesn't run, direct feed
it some power.

Personally, I've been having some trouble with coils once in a while. I had
a problem where my coil drew enough amps to blow the ECM fuse. You might
check that fuse.

It has both a cam and crank sensor. When you start it, after everything
turns over, it figures out where it is. If the cam and crank sensors aren't
aligned, it'll never sync up and it won't start. So there's one
possibility, jumped timing or a broken timing belt. It's pretty easy to
check. The front engine cover is split at the crank, so you can that whole
thing off without doing a whole lot to the front of the engine. There's
also a little piece of the front cover that allows you to see the belt up in
the upper right corner.

The two sensors could be at fault. I don't know if they'd set a code in the
condition you've got, where the engine won't run. Hard to say.

 

I have to say, this is one of the most competent threads I've ever seen on
USENET. I sure hope the OP is taking all this in. Great answers from
everybody so far.

 

Well the lab scope is currently beyond the means of this backyard
mechanic... I'll look into inspecting the timing marks, after I try to
check for codes with the good ol' key trick. With any luck I'll take a
look tomorrow, after swapping engine mounts on my GCL.

I honestly doubt it. How many people out there buying used cars ever
think of such things?

 

The very first thing I asked about was if it was sparking, and without
any tools onhand I went towards the fuel pump. No life from the pump
and very little from the ignition (apparently). My next thought was
crank/cam sensor but not knowing the engine, I had no idea if it even
had one or not. *shrug*

Ah, shouldn't the system prime even if one of the sensors IS bad? I
cycled the key from off to run several times, taking the key all the
way out each time, and was greeted with nothing from the shrader valve
on the fuel rail.

I'll try the fuse. He mentioned that someone had tried a different
coil pack, although if it took out the fuse then replacing the part
certainly wouldn't help.

Still, there should be *some* pressure at the rail shouldn't there?

 

It has both. Crank sensor is on the lower rear passenger's side of the
block near the transmission bellhousing. Cam sensor is the most obvious
thing sticking up from the top of the driver's side cam gear cover.

Yes, the system should prime after you turn on the key and before
starting the engine. The fact that it doesn't points to a fuel pump,
fuel pump relay, or auto-shutdown relay failure. Check the relays first,
they're cheap and easy.

 

While checking for fuel pressure I swapped the FP relay with the A/C
relay (supposedly the A/C worked) which didn't help. The auto-shutdown
relay is a great idea though, I hadn't considered that and it does
make sense. I loaned the owner my battery charger today, so hopefully
we'll check out a few things this week.

 

Well for a quick update, I finally had a chance to take a quick look
before the rain came on. A couple of mechanics have looked at it in
the meantime with no luck. There's fuel at the rail now, although
someone may have just powered the pump manually. I still don't hear it
when cycling the key. Swapping the ASD relay for the starter relay
didn't help, she still cranks with no other signs of life. I tried
checking for codes and I can't find the CES light for the life of me!
Even during the self-diagnostic when the key is first turned, no CES
light to be found. Hmmm... It's possible that someone pulled the bulb
somewhere down the line. All known fuses were checked by the
mechanics, and just for the hell of it, she won't fire in neutral
either.

He was told that the wiring harness that runs from the PCM down along
the bottom of the rad is a common failure point for these cars. First
I've heard of that one.

 

When mine started blowing the PCM fuse, I looked at that harness and said "I
bet there's a problem down here," but there wasn't. It looked like a bad
place to run the harness to me, but mine was fine.

In my opinion, you'd really be making a big mistake not to concentrate on
getting that PCM light on. If the bulb is good, and it won't light, I think
that really helps you make some decisions.

 

I agree completely, although I'm not even sure where the CES light is
supposed to be on that thing. The lights to the left of the dash look
pretty well populated but only one lit up in that row off to the right
(ABS I think). Ugh... I'd hate to have to tear into the dash on a
neighbor's car who doesn't understand the reasoning and wants to watch
everything I do. I'll try to talk him into it when I see him. lol