Amber Gramps

basically I replaced the fuel check valve per Steve Weiner's suggestion because the engine didn't fire on first tap of the key. It seemed to do the trick until it sat for several hours and the problem returned.

Per Steve I can still do a few things like replace the filters, the pump, or the regulator, or the chip. first I want to know about pressure though....so.....

I went down this morning and got my self a new toy. The gauge is an off the shelf item that I took to a hose shop for modification. It cost a total of about $62.

It looks like my system has about 34psi and drops to about 30psi when I crack the throttle.

Here are the parts I used:

1) fitting part# 4G-6FDLORX $9.00 each x1 this is the M12X1.5 end that goes on the test port.

2) fitting part# MPT-4-2 $1.97 each x1 this end goes into the gauge. (It's a 1/4"MIP)

3) 7323 brass crimping ferrules $2.00 each x2 The hose shop made them look perfect.

4) 1/4" instagrip 300# hose (1.3 feet) $5.15 x1 identical to what I took off the gauge.

5) 100psi. fuel pressure gauge from Pep Boys $39.99

It's been on the fuel rail for about 45 minutes. . . .

rusnak

That's a pretty sweet gauge. I think you're a tad low on pressure but I don't think it's a problem. You might get a remote starter switch and spark tester.

Amber Gramps

After 1 hour the pressure was still at 34psi and it didn't fire.

rusnak

You might check voltage at the icv connector, then dme grounds if it's borderline 12v. You need at least 12.6 or so at the battery. At 12.4 your starter will spin, but the injectors won't open because they will be barely getting 12v. You might have a weak battery cell or two if the battery won't charge past 12.5v.

Also, excessive ref sensor gap will cause hard starting.

theiceman

... put your stock chip back ..
if for no other reason than to eliminate it

User 4221

+1.... Eliminate an obvious variable

Amber Gramps

After 5 hours I still had 25psi but the next morning I had zero.

Also....I did change out the chip and the problem persisted.....so I went to the next step with the tools I have.

I hooked up my timing light to the battery in my van and put the test lead on plug wire #1. At first tap of the key the timing light did not light up and only flashed sporadically after 10 seconds or so. Turning off the key and turning it back on did cause the light to flash and the car did fire right up. Actually, I got a variety of results, but most of the time the car was running by the second flash of the light.

I'm thinking it's a bad coil. Also, when it did fire up I noticed that it would mis-fire and smelled of raw fuel. The plugs, wires, cap, and rotor all have less than 15,000 miles on them, but the coil is most likely 23 years old.

theiceman

could it be a failing reference senor ?

Amber Gramps

It very well could be. It's the intermittent part that puzzles me though. My head keeps going back to bad coil or bad signal to the coil. Here is what I found just an hour ago when I had 5 minutes to run by the house.

I hooked up a test light to the +/- terminals on the coil. I thought the lights would come on as soon as I turned on the key, but they didn't. For some reason I was thinking the coil gets a constant 12v, but I guess not. ....or does it? ....anyway, it didn't fire.

I turned off the key, checked the fuel gauge and it was at 35ish so I went back and tapped the key. This time I noticed the lights flashed when I turned the key on and when I hit the started it fired right up, the lights flashed and they stayed on till I shut it off. I repeated this several times and it fired at first tap repeatedly.

Now I'm just confused and heading to Disneyland for the evening. Dad stuff, ya know.

A coil is right at $65. Should I go get one and see if that's it, or are you guys gonna make me do more testing???

rusnak

You should get 12 to both sides of the coil with the key on. You will probably ohm out the coil, but only way to test it is under load. The ref sensor can be ohm tested, but franly I think it could be the gap, especially if the hard starting is worse in cold weather.

I'd also test the dcv at the icv. You,want at least 12v. 12.2+ is even better.

I think one of your injectors is bad, and could be pissing fuel into the engine.

theiceman

i think you can put the fuel gugae away its ignition . For intermitemnt problems you cant ohm anyrhing out coz it will show good.
personally i dont think you can go wrong having a spare coil.

Amber Gramps

I believe you are 100% correct.


You got all that from looking at aeroman's avatar, didn't you?

OK, I got out of Disneyland by picking up the baby and putting her in her bed. . .

First thing I did was disconnect the positive terminal from the coil. I put a multi-meter on the positive wire and ground it to the motor. Turning on the key and heading back to the meter it said 5.4volts but then I shook the ground and it went to 11.75volts. Note that my oil cooler fan is hardwired to come on with the key and that may account for the 11.75 vs the more desirable 12.something. Upon wiring it back up it did fire at first tap.

I refuse to think it was just a corroded terminal.

rusnak

You know, Aeroman's avatars ARE inspirational, and they make tech problems become crystal juggies. I mean, crystal clear.

Ed Hughes

The failing sensor could be a winner....or could the mount bracket have come loose?

Amber Gramps

I can't see it being a loose bracket as leaving the key on a while prior to tapping the starter seems to do the trick. Will let you say "I told you so" for a year if that does't do it. You can even give me crap for asking permission to spend $65 if that will help.