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SES always on - no codes other then 12

I am unable to rotate that knob to change the pressure unless I loosen the TB. I did bend the vacuum line below it some but it is still too tight.

I took it to a local transmission guy for his opinion, he took it for a ride and reports that the trans if fine but he hears that one cylinder, he thinks, is missing.

Also checked the timing. Zero degrees with that electric line to the right of the brake thing disconnected.


Remember wire, plugs are new, I never did replace the cap and rotor, what do you think... Cap is at least 10 years old. should I replace it.
 
THEMCGUIRE said:
Remember wire, plugs are new, I never did replace the cap and rotor, what do you think... Cap is at least 10 years old. should I replace it.
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:doah:

Yes! Even if this is not the issue! The rotor button in these caps is known to fail and still run. You will see black tracking from arcing in rotor as soon as cap is off if this is the case. Also what happens is button is spring loaded to push down on rotor and the spring faisl, it just hangs there.
 
Thanks, ok will replace them tomorrow.

btw, I dont hear a misfire, but I am inexperienced.

I think I have heard misfires before but they were quite noticeable, to me anyway, this misfire that the trans guy is reporting is very subtle, but he does more than trans work as well.

Bending to the ear of the more experienced...
 
Is it the original distributor?

You *might* want to just replace the whole thing.

Normally I'm not a fan of this, but if you are going to start digging into it, and dumping money at the distributor, oftentimes these things are cheap enough, new, that it's not very hard to justify a complete replacement. Oonly reason I mention this is that the distributors (and components) on these rigs are fairly problematic at this age, and if the pickup coil goes, the whole thing has to come out to replace it, it's $20, the module is $40, cap/rotor another $20? Adds up pretty quick.

Cap/rotor are very, very basic. If you take it apart, and there is no wear, loose terminals, cracks, tracking, or erosion, and the rotor contact is in good shape, it's fine. There is no magic to a cap and rotor. If there is a problem, you will see it. I'm cheap.
 
If I were to replace the distributor what should I get ?

I looked and there are a lot to choose from. I looked at NAPA and Summit and a few other places. I am not trying to build a high performance engine just want reliable, fun to drive, truck.

Price range is from $90 for a Cardone Re-manufactured to $400 for a
Mallory Ignition 9548204 - Mallory Aftermarket Fuel Injection Distributors


Do I need HEI?

Do I replace the coil at the same time ?
 
Coil depends if you have big cap or small cap. If you have big cap, the coil is part of the assembly. I don't know the breakdown for TBI on coil in cap or remote...all truck ones might be remote? All of them are HEI from '75 onwards. Difference is whether they have vac/mechanical advance, which EFI doesn't of course.

I can't really comment on quality. $400 seems a bit expensive, but if someone lists an AC Delco replacement, that should be the "gold standard" presently in terms of price.

EagleMark has seen differences in the way the aftermarket ignition modules perform. But as you see, for $90, it's hard not to go that route.

Wait for more opinions before you just throw the distributor out. As an example why I somewhat lean this way: my buddy with a 1996 Tahoe, and myself, with '88 Camaro injection (which both use the same or similar distributor as yours) have both been stranded in the last year when our distributors died. Mine was the pickup coil, his no idea as he just replaced the whole thing. But I spent $40 guessing on a module, and $20 on the pickup coil, as I had no diagnostic equipment.

However, almost all aftermarket parts that are cheap or reasonably priced, are questionable if they are any better than 20-30 year old factory parts. You often just have no idea what you are getting, and how long it will really last, when the OEM stuff lasts sometimes forever.
 
OK I will wait for new opinions on distributor.

Back to the fuel pressure regulator. I spent 85 bucks on it . What is the point if when I install the regulator and have the screw tightened up just touching the spring compressor and I am at 15 psi.

It is suggested that the 100 psi gauge may be off. It looks like it is a brand new gauge the I rented from auto zone.

I bought a 15 psi gauge but the hose that I bought does not have the connector on it that will open the Schroeder valve on the fuel line adapter.

What is that connector called ?

Very frustrating, I do not know how movement on the adjusting screw will affect the pressure. I have to remove the fuel lines in order to turn the screw, I am very very worried that I will strip those fuel connections putting them on and taking them off over and over again.

How much does the fuel pressure change with 1/4 turn or 1/2 etc. ? If the gauge is right ??? what is the effect of too much pressure ?

finally, should I remove the TB so I can control how much I bend the vacuum line to have any chance of rotating the adjusting knob without removing the fuel lines repeatably ?

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Edit: 5:17 PM....

Took the fuel lines off tightened the pressure adjustor knob to 1/2 turn tighter than just touching... No change in pressure on this auto zone gauge --- still 15 psi... wtf... I feel that this $85.00 bucks was a waste of money.

Put the new cap and rotor on. The old cap has a lot of green on the brass. No scoring Take that back looked at it under better light. Brass is black. There are many tiny lumps, that look like slag, on the sides of the inside brass ...

Took it for a ride and it's much better on acceleration.

I can feel it in the seat of my pants again. :)..... however it still sound the same as yesterday when that trans guy said he heard a misfire. The th th th th th th is still there but feels nice now. Is it just me...

Appreciate any thoughts...
 
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If you can tell something is wrong with the motor, I'm like you, I would not be comfortable until I figured it out.
 
If you put the stock spring in the adjustable regulator it will compress spring a little more then stock so you will have more pressure. It may take tightening up the spring half way to get another 1 lb, but with an aftermarket 18 PSI spring the adjustments are very small.

SO you have 15, verified on two gauges. Good, call it quits. Even a stock motor needs at least 13 PSI to run as it should and 14 is better. 15 is a little more then needed but BLM learn control will compensate and if you ever data log for fine tuning it can be done properly because you have enough pressure. Effect of to much pressure is you will run rich. But 15 PSI on a stock motor is within BLM learn capabilities and is corrected. SO no ill effects.

My take on distributors is AC delco because of the EST module. If the reluctor wheel up top shows no signs of cracks? Then I do take them apart and replace the pich up coil, then cap and rotor. EST modules seem to last forever without human interference so I leave them. There are 2 EST modules from GM and they only put out one now. One used to take away timing at 3000 RPM and one adds. The aftermarket are all over the place and you just don't know. There is a specific setting in the chip known as "SA - Spark Latency Correction" and it is in msec, if you have an AC part it is already set.

Seems like your cap and rotor fixed the issue... but you hear something? What kind of exhaust is on truck? Could be just the way you hear it? If you truly beleive there is a miss? Then you could pull all plugs and visually inspect to see if one cylinder has an issue?

There are O ring and plastic seals on those fuel lines you've been taking on and off. Please be sure you have no drips!!! I had no idea you were a novice at this when we started.

You don't want the schrader valve in a permanent install, that is for temp mounting of a gauge. the hole in CFM adapter is 1/8th NPT and your gauge line is probably a AN. So proper brass adapter is all you need.
 
dyeager535 said:
If you can tell something is wrong with the motor, I'm like you, I would not be comfortable until I figured it out.
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Exactly dyeager, I am always concerned that if it is not spot on I will have some problem because of it in the future.

eagle mark said:
SO you have 15, verified on two gauges. Good, call it quits. Even a stock motor needs at least 13 PSI to run as it should and 14 is better. 15 is a little more then needed but BLM learn control will compensate... Effect of to much pressure is you will run rich. But 15 PSI on a stock motor is within BLM learn capabilities and is corrected. SO no ill effects.
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Do you think I will pass NJ emissions test with this rich fuel ratio?

eagle mark said:
Seems like your cap and rotor fixed the issue... but you hear something? What kind of exhaust is on truck? Could be just the way you hear it? If you truly believe there is a miss? Then you could pull all plugs and visually inspect to see if one cylinder has an issue?
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The exhaust system is from NAPA. It was replaced from the headers back (i.e. New cat and muffler and pipes) with what NAPA said was stock replacement. (The new CAT is like a 1/3 of the size of the original but they said it was stock replacement)

Well it certainly feels better. But I do plan to pull the plugs and take a look at them after I have driven it at least 50 miles. (Been about 6 miles and a couple of hours of idling, so far).

eagle mark said:
There are O ring and plastic seals on those fuel lines you've been taking on and off. Please be sure you have no drips!!! I had no idea you were a novice at this when we started.
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I bought new O rings (damn $2.50 each) before my final install of those fuel lines. Checked super careful. No leaks, it took me about 1/2 hour to get those lines in but I could not take a chance on crossed threads as I mentioned in an earlier post. I have removed the adapter from the fuel line.

I am a bit annoyed that I can't leave it in because when I ordered the fuel regulator from CFM I placed the order and then realized I needed their adapter. I called and emailed immediately. Then the next morning I called and emailed again. I wanted to add the other item to save on shipping.

I have yet to hear back from them.

So "F" them...:) I will do without a permanent installation of adapter for now.

I will advise after I pull the plugs and inspect them. But there is quite a bit of carbon at the tip of the exhaust. I will get the cap on asap and take if for a long drive and then go to Motor Vehicle inspection. If I fail I will pull the plugs asap.
 
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cfm is notoriously not very good with communication these days..

not sure on Eagles reasoning about schrader valves, but every Merc MPI setup I've ever seen has a permanent schrader valve in the system under higher pressure than a TBI... never seen an issue with them...

I pass NJ sniff with 14 psi easily...

tho I like MSD billet's, absolutely nothing wrong with a Delco dizzy.. I'm not a fan of recent Mallory offerings..

oh, and just not to confuse this thread with another that's bouncing around, you do have stock exhaust manifolds, correct? saying headers will definitely confuse the issue sometimes..
 
Do you think I will pass NJ emissions test with this rich fuel ratio?
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Yes.

When I say rich it is what the BLM or Long Term Fuel Trim is adjusting. SO tailpipe is not rich, ECM is correcting for rich.

For emissions I would have the new cap and rotor as well as a fresh set of plugs and oil filter change and drive 100 miles for BLM learn to be well done!

If you have to wait in line... (Like I did when I lived there 20 years ago...) put a paperclip in A and B slots of ALDL port while waiting and idling. This puts ECM in ALDL mode and raises idle to 1000 and increses timing. This will keep the engine running clean as well as O2 sensor and CAT hot. Works like a charm. Pull it out before they see you.... :whistle:

Your cat is the newer honeycomb style and should be fine. Origanal is monalethic. It's funny how they changed about the same time as TBI went to MPFI. They do work differently.
 
ryoken said:
not sure on Eagles reasoning about schrader valves, but every Merc MPI setup I've ever seen has a permanent schrader valve in the system under higher pressure than a TBI... never seen an issue with them...
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It is for temporary connection and has seals there's really no issue with leaks. But also no way to tighten for permanent.
 
went back and looked, is that a quick connect coupler setup? I thought you where talking about the actual Schrader valve..
 
I was talking Schrader. It's OK, but it is not meant for permanent installation, there is a better way.
 
like I said, I see it every day as a permanent install on various factory MPI's...... ya put a cap on em, no sweat...
 
I think he means if you thread a fitting on them, and use that to run a permanent gauge?

You are talking that the schrader being permanently fixed in the setup? It is on TPI as well of course, just not running a fuel line from it permanently.
 
oh, yeah, I'm not talking with a hose/gauge on it, just the Schrader... but there's no reason you couldn't leave the adapter in there with no hose hooked up......
 
I think Mark's point is there isn't a good seal between a Scrader and whatever is attached to it.

I assume the guage/line adapters thread onto the valve, but a Schrader isn't pipe thread AFAIK. Teflon would maybe do it? Amazingly I've never had to deal with the TPI Schrader valve, but that's likely going to change soon.
 
yeah, we just use em to check pressure on test runs... my issue with leaving a permanent hose would be they are most often a hand tightenable knurled connection, pretty easily bumped and not very torque verifiable......
 
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