Help! Weird rough running issue after fuel reg adjustment....

[Speed metal]

I installed a fuel pressure guage in the high pressure part of the loop near the DS fuel rail.Checked pressure,and it was high.( this would explain why the car was running rich)I adjusted down to 29 ish and the car idled smoother. Went to back out of the shop, and it kinda sputtered and died.Got it to start again, running rough! Like 3 cylinders rough! I put the pressure back where it was originally(. Car actually ran nice before i farted with it) if i pull a lead from either injector it will start but runs the same. ROugh. I have spark to each plug( though it seems wimpy to me ),and i checked for continuity through each injector plug. WTF? if i pull either plug wire, it starts but runs the same. No more or less rough. It seems like the whole drivers side is dead!

Sigh... Is it possible that the regulator unleashed a load of **** down into the injectors on the drivers side when i turned it out?
Did lowering the fuel pressure cause something else?
Its all stock save for pertronix. This car ran nice, started every time etc before i farted with the reg.

Thanks in advance!

[Mike Bellis]

Most regulators need to be on the return line, after the rail and before the return hose to the tank. This keeps the rails at 29psi (or whatever setting). If placed on the supply, you only keep the supply hose from the pump pressurized and effective zero pressure at the rails. Effective zero pressure because there is little restriction back to the tank.

[Speed metal]

I never moved the reg..... Only added a guage! The reg is in stock location. Just put new plug leads on.... No different! Pulling injectors now...

[John Rogers]

If you run the fuel pressure back up to what it was before, does the engine run okay then? If so it could be injector issues that were clouded by the high fuel pressure? Another thing you could do is put the old plug wires back on too and see if it is okay?

[Speed metal]

I actually put the fuel pressure back up right away. No change!i just put new wires on this morning. No different than the old ones. Harness seems fine, injectors fire when turning it over.New injectors 3 months ago. Not clogged, just checked. Did i roast the head somehow?

[jsayre914]

is this a 2.0 motor ???
are we talking D-jet ??

[Speed metal]

Yes, DJet.2.0
Is it possible that the reg is buggered? Bypassing too much fuel?Air in the lines?Reg was hooped. Replaced it with a knows working unit. No change..

[strudelwagon]

hey Speed, did you install the gauge on the line going to the cold start injector? this would be the high pressure side but not part of the loop. That injector on lt adds fuel on cold mornings and the rest of the time it's not in use. You probably already knew that.
SW

[Speed metal]

Originally Posted by strudelwagon

hey Speed, did you install the gauge on the line going to the cold start injector? this would be the high pressure side but not part of the loop. That injector on lt adds fuel on cold mornings and the rest of the time it's not in use. You probably already knew that.
SW

Nope! Its in the proper loop...

[John Rogers]

The new wires may be the "same" as the old ones, but I would put the old ones back on to try. In the working around the distributor, did you loosen the plug for the trigger points? Finally what do the spark plugs look like?

[Speed metal]

Originally Posted by john rogers

The new wires may be the "same" as the old ones, but I would put the old ones back on to try. In the working around the distributor, did you loosen the plug for the trigger points? Finally what do the spark plugs look like?

Tried the old leads and the new.The trigger points plug is still plugged in.I checked it almost right away.The plugs looked a shade moist.
What are the odds I dropped a valve?Is it possible to lean it out with the regulator too much?I have run it rich for awhile...
Ive gone over every connection,injector,and replaced the reg.(which was failing/bypassing)Replaced the dist cap...Its running pertronix,and if its crapped the bed,its a fluke and unrelated to me installing a fuel gauge!

[Dave at Pelican Parts]

If you dropped a valve, you'd know it. If you dropped a seat, the starter would sound very uneven. "RR-RR-..-RR-RR-RR-..-RR-RR-RR-..-RR" Same goes for anything else giving you zero compression on one hole.

If you leave the fuel pressure reg out of the circuit, you will get very close to zero fuel pressure. The stock regulator acts as a restriction on the "downstream" end of the high-pressure loop. Think of it like putting your thumb over the end of a garden hose; the pressure inside the hose will go up. The regulator is that thumb.

Let's check the basics: Do you have spark on all four? Hunt down an extra plug and a friend who can crank the starter for you. Tape the plug with the threaded part or the outer electrode touching ground, and then crank the starter. You should be able to see the sparks at the plug. Make sure all four wires are producing sparks.

Are you getting fuel? Do you smell fuel at the tailpipe after cranking the starter for a while? For a finer-grained answer, remove the injectors from the manifold (and unplug the points/points-replacement from the coil). There's only one M6 (10mm wrench) nut that holds each injector to the manifold, you can remove the two nuts holding both injectors on one side and then pull the injectors and the fuel rail up away from the motor. Put the injectors in separate clean (ish) glass jars, or one large jar. Have someone crank the starter while you look at the injectors. You'll see if fuel comes out of all four injectors, and you'll also get to see what sort of spray pattern they have.

If you have those, then do a compression check. But as I said, one bad cylinder will generally be obvious when you crank the starter.

Once those are verified, the only variables left are the spark timing and the amount of fuel going in.

--DD

[Speed metal]

Originally Posted by Dave at Pelican Parts

If you dropped a valve, you'd know it. If you dropped a seat, the starter would sound very uneven. "RR-RR-..-RR-RR-RR-..-RR-RR-RR-..-RR" Same goes for anything else giving you zero compression on one hole.

If you leave the fuel pressure reg out of the circuit, you will get very close to zero fuel pressure. The stock regulator acts as a restriction on the "downstream" end of the high-pressure loop. Think of it like putting your thumb over the end of a garden hose; the pressure inside the hose will go up. The regulator is that thumb.

Let's check the basics: Do you have spark on all four? Hunt down an extra plug and a friend who can crank the starter for you. Tape the plug with the threaded part or the outer electrode touching ground, and then crank the starter. You should be able to see the sparks at the plug. Make sure all four wires are producing sparks.

Are you getting fuel? Do you smell fuel at the tailpipe after cranking the starter for a while? For a finer-grained answer, remove the injectors from the manifold (and unplug the points/points-replacement from the coil). There's only one M6 (10mm wrench) nut that holds each injector to the manifold, you can remove the two nuts holding both injectors on one side and then pull the injectors and the fuel rail up away from the motor. Put the injectors in separate clean (ish) glass jars, or one large jar. Have someone crank the starter while you look at the injectors. You'll see if fuel comes out of all four injectors, and you'll also get to see what sort of spray pattern they have.

If you have those, then do a compression check. But as I said, one bad cylinder will generally be obvious when you crank the starter.

Once those are verified, the only variables left are the spark timing and the amount of fuel going in.

--DD

Checked spark on the side I was working on.We have spark..Checked the injectors..Good there.I have to listen closer to the starter..
When you say "If you dropped a valve youd know it"Please elaborate..
Also,is it possible i fried the pertronix?How would it act if I did?

[Dave at Pelican Parts]

If a valve actually dropped, it would make a horrible racket as the piston smashed into it.

Valve seats can drop and not cause valve-piston collisions, but they will cause a loss of compression.

Verify fuel and spark on all four cylinders, just in case.

A failed Pertronix usually just won't give you any spark at all. I have heard of them starting to fail and giving inconsistent sparks, but that is less common. Still, it may be worth trying points again to see if that helps.

Once you know you've got spark and fuel and compression, you can check the static timing of the spark. You can do that by setting up the motor to TDC for one cylinder, and using your extra spark plug on that cylinder's plug wire, tweak the distributor until it sparks right at TDC. That's not the correct timing, but it is more than close enough to start. (If you can get your engine to run at 3500 RPM, then use the regular timing instead of static.)

After that, the question is the amount of fuel. Too much or too little...

--DD

[r_towle]

So, everything worked prior to this project.
Go back to the beginning and the basics.
Check them again.

Firing order is 1432
Injector wiring...injector grounds, CHT etc.
Distributor trigger points
TPS plug

Sounds like its either the firing order is wrong or the injector wiring got unplugged some how.

rich

[KWales]

A lot of times, bad performance come from a change that was made. The fact the car ran well before suggests adding the gauge caused the problem. I'm guessing it was installed in the rubber line.

Lets see:

Did you spray clean the inside of the new gauge before installing? If you didn't, dirt may have blocked something.

Does replacing the gauge with a piece of pipe solve the problem? If it did, it's the gauge.

How old is the fuel hose near the gauge? Did the pushing and pulling on the rubber hose separate the inner gas liner from the outer woven part of the hose and create a fluid pinch point in the line? This sometimes happens with the old rubber brake hoses.

What did you touch near where you were working? Disconnect a ground? break a wire? etc.

Hope that helps.

[Speed metal]

Originally Posted by r_towle

So, everything worked prior to this project.
Go back to the beginning and the basics.
Check them again.

Firing order is 1432
Injector wiring...injector grounds, CHT etc.
Distributor trigger points
TPS plug

Sounds like its either the firing order is wrong or the injector wiring got unplugged some how.

rich

Its crazy!I checked the injector plugs with a loose injector..Click!Click!
I didnt actually touch the plug wiring initially...
Trigger points?Maybe just a coincidence?
TPS plug is good.
I checked the spark off each lead with a loose plug.It sparks on all 4.
I havent checked the other 2 injectors(opposite side)
Again,if the pertronix craps out,would it cause this sort of grief?

[Speed metal]

Originally Posted by KWales

A lot of times, bad performance come from a change that was made. The fact the car ran well before suggests adding the gauge caused the problem. I'm guessing it was installed in the rubber line.

Lets see:

Did you spray clean the inside of the new gauge before installing? If you didn't, dirt may have blocked something.

Does replacing the gauge with a piece of pipe solve the problem? If it did, it's the gauge.

How old is the fuel hose near the gauge? Did the pushing and pulling on the rubber hose separate the inner gas liner from the outer woven part of the hose and create a fluid pinch point in the line? This sometimes happens with the old rubber brake hoses.

What did you touch near where you were working? Disconnect a ground? break a wire? etc.

Hope that helps.

Gauge was brand new and so is the tee.Cleaned inside.
I havent tried replacing it with pipe..I cant figure how a gauge in a tee could cause grief?
Hose is newer and pliable.I will check for a pinch...

Ive looked at all the wiring n the adjacent area,and avent found anything amiss...
Injectors fire,leads spark,Building proper fuel pressure.

[strudelwagon]

Speed, I know this sounds stupid but have you tried swapping out the MPS. I had a hell of a time with mine with running rich and next to no idle. It was fine when I took it all apart but for some reason it went bad. as soon as I plugged in another MPS, the idle smoothed right out.
Not saying it's you answer but a pretty easy check with 1-plug and 1-hose. You don't even have to bolt it in. Even a good 1.7 one will make it idle.

[John Rogers]

In fiddling with the injectors it is possible that one or more has come lose and either the large and/or small donut seal is leaking badly. I would suggest pulling each, do a capacity AND spray pattern test and at the same time see if the seals are okay I.E. soft and pliable and also that each injector has the plastic cap on the end.