97xray

***UPDATE BELOW***

Hi all.
I'm at the point of looking for help: motor won't start. I sifted through the first 30/40 results to a "no start" search - but haven't found anything exactly like my situation yet.

Here's what I've done:
-the fuel rail has fuel, but I don't know about the injectors (also, I believe I hear the fuel pump when I turn the ignition, something I've listened for before)
-replaced plugs; they were a bit fouled anyway
-(very) good spark to and from distributor to each cable
-starter is engaging, motor is cranking nicely
-motor started and ran for several rotations (maybe a couple seconds) on a small amount of starting fluid

How does one check the injectors? The DME relay is only ~1 year old, but the other relays are about 25 years old!

I here a slight taping when I open the throttle and am cranking, seems to be from the AFM area, or at least the front of the motor. That may be normal, but I don't remember it from earlier escapades with the motor!

The car sat for two months (winter) before I recognized the problem when trying to do a belated winter thaw (warm up the motor, basic maintenance, etc)! Belts were retensioned about 500 miles ago, front-end rebuild about 10K ago, typically runs like a champ.

Thanks in advance!

schwank

Pull the injectors and fuel rail out in one piece. Put four pop bottles under the injector nozzles and turn the motor over... if they are firing, you'll see the fuel.

The tick is the throttle body opening when you press the accelerator.

jpk

If you have a stethescope (or just listen closely while someone else cranks it), you should be able to hear the injectors clicking. If they click and you have fuel pressure, they're OK.

What does the tach do while cranking?

I'd suspect the engine refrence sensor; this is what tells the DME where TDC is (or some other known point in the rotation). Based on this the ignition and fuel timing is set, without it, you'll still get spark, but it's not at the right time (advance is off)

When the refrence sensor went bad on my early car (really it was just the connector at the back of the cam tower that crapped out) I could actually get the car to start and run (albeit very poorly) if I held the throttle wide open and cranked for 20-30 seconds; when it did start and run, it was really rough untill it slowly gathered speed; around 3-4k rpm, things smoothed out and it ran almost normally. Essentially what was happening was that the ignition timing was running at the default timing; it was not being advanced or retarded as it should be.

Todd157k

did you check to see the maf is plugged in and working?

quinnfiske

Get a NOID light. Mine was under $5 at Autozone. Unplug one of the injectors and plug this into the end of the cable. It was made for Bosch injectors and has an LED in it. It will glow when the engine cranks if the DME is supplying an injector signal.

2BWise

Another thing to check. The fuel rail has fuel, but what about pressure. A faulty fuel pressure regulator can also cause a no start issue

ivai

Easy way to check the fuel pressure regulator (if you don't have a gauge): unplug one of the injectors.. if it starts with only 3 injectors receiving electricity, this most likely means a bad fuel pressure regulator. Reason being, when the FPR fails, it typicall fails in the closed position, causing fuel pressure to go really high, and the DME can't supply 4 injectors enough power to open up against the pressure, but it can power 3 under this condition.

http://clarks-garage.com/shop-manual/fuel-01.htm
http://clarks-garage.com/shop-manual/fuel-07.htm

97xray

Thanks for the great tips, guys.

I replaced the FPR in the past five years, but I guess I should check to be sure all's well.

I thought of the speed & reference sensors as well, but the tach "bobs" normally at very low RPM values. If any of you have a good picture of the reference sensor location, I could use a pointer to which plug it is back in there!

Any special tips on pulling the whole fuel rail with injectors? In the mean time, I'll try a NOID light to the injector(s) - as well as just listening carefully.

Keep the ideas coming!

jpk

The fuel rail should come off pretty easilly, it's just the four bolts holding it in place. The injectors themselves are just press fit in with the o-rings. If you havn't doen it recently, you might want to send them out for a bench cleaning; the injectors will come back like new.

The tach is fed by the engine speed sensor only, so that doesn't rule out the refrence sensor. As far as where the sensor is; they're both on the same bracket. You should be able to see it from the top. The refrence sensor is the one further forward; the speed sensor is closer to the firewall. The wires and plugs for both should come up to a bracket attached to the back of the cam tower. Both connections look the same; the sensors themselves are intechangeble.

Chances are, when you take apart the connector to check it, the plastic will just crumble in your hands. You can get replacements for the female side of the connector (harness end) it's a pretty standard 3-pin AMP connector. Unfortunately, it doesn't appear that the male end is avaliable seperately; you need to replace the entire sensor. If you do some searching, you should be able to find replacements for around $60 each.

Rock

+1

Dont take the rail off, thats extra work.

97xray

For various reasons - none worthy - I've been sidetracked on the no-start problem. I've recently had a chance to get back to it and found the following (pics below) when I pulled the injectors... which leads me to two follow-up questions:




(1) In the pictures above, why is one injector so different from the others? It appears the dimensions of the portion that sprays are substantially different. From a quick search on Which Hunter's website, the odd injector looks like a high-flow LUCAS type. Any ideas why that might be in there? (Aside from having a stupid previous owner...) Can I continue using it (it's been OK for >10K miles thus far...)?

(2) RE. speed & reference sensors: I checked the plugs, cables and what I could of the speed and reference sensors themselves. They appear to be in great condition - no cracking on the cable housing, connectors, or attachments. Since so many posts describe the connection and/or cables being brittle and dry, it makes me think they could have been replaced just before I bought the car. Is there a way to test the sensors empirically? I'm pretty familiar with an ohmmeter and voltmeter.

My thread-opening post covers the basics of the no-start. I've since read many more the of the hundreds of search results but still not all of them!

Thanks!

quinnfiske

You should have 4 injectors of the same type, but since the car ran before, your immediate problem is probably not that.

If you want to test the speed and reference sensors go to www.clarks-garage.com/ and look under the "Garage Shop Manual" section for "Speed and Reference Sensors". You can check the resistance with an Ohm meter.

97xray

I'm still not able to start the motor and am just about to a point of taking it to a well-respected mechanic... I haven't taken the car to a mechanic in almost 6 years.
Before I throw in the towel, I wanted to update this thread and ask for one more expert review:

(1) I have brand new fuel pressure damper and regulators and have seen fuel expelled from the injectors. Additionally, the NOID tester showed equally timed pulses to each injector harness point.

(2) I have new spark plugs and spark is getting to all four cylinders (used a Bosch tester there, too).

(3) The speed and reference sensors pass Clark's Garage Ohm measurement and are in great physical condition.

(4) The DME seems OK, tach bounces properly, battery is charged, relay was replaced 2000 miles ago.

(5) Visual inspection of motor, AFM, fuel lines, vacuum lines - EVERYTHING - looks good. (No mice!)

What am I missing?! The motor has fuel and spark and is turning like a champ. Isn't some law of physics failing me here?!

It sat for about 9-10 months without being started, but with dry-gas and 2 gallons of 93 octane premium fuel added every few months (did it twice in 9-ish months). Could it be the gas is bad??? I find this incredibly hard to believe.

Thanks, guys!

2BWise

Since you've got fuel and spark you've eliminated a lot of potential problems. Since you have a voltmeter, go ahead and test the TPS, AFM, and then the DME. My bet would be that the DME is getting a faulty signal from the either TPS or AFM and leaning/richening the mixture and that's causing your no start. Or the DME is the culprit all along.

Todd157k

I think along the same lines as you... there's some physics here. Gas+Spark+compressed air= boom. What has me thinking is that you were able to run it with quick start. That just needs very little air. Are you sure the cam hasn't skipped or the belt broke? or something? I would look at the TDC and make sure the cam is in the correct spot. When it runs on quick start, does it run good?
Another thing (question, not debating) since he has spark, why would you think it's in the DME? Wouldn't that kill the spark?