Idles and runs terrible

[835.0RS]

If I knew what to look for I would go past posts but am lost right this minute. Went driving in our 85 and though it hasn't run perfectly since we got it now it is really bad on returning. At idle it is rich and maybe 2-3 cylinders is all it seems to run on, we have codes 21, 23, 25, 34, 54,and 77. we think it is fuel related? as we checked for spark all cylinders-good, has new wires, new plugs, new dist. guts, turbo is new, starts right up but boy is it sick! Any thoughts on this greatly appreciated.

[Laredo]

PM sent

[SVOeric]

?? Why PM (unless you're offering to go over and help him, which I doubt, cause you're in WA, and he's in MO) -- post your suggestions here, so we can all see, and can make sure we aren't all giving the advice.

some of the first things to check for are,
Stuck VAM (make sure the flapper door moves freely)
holes/collapsing VAM to turbo hose
fuel pressure
PCV valve loose

from your codes....
Code 21 -- Engine not up to temp, pretty much makes the rest of the codes no good-- UNLESS -- the engine really was warm, then this points to the ECT temp sensor, and will certainly make the car run bad when warm.

Code 23 -- TPS out of range -- this will certainly make the car run bad as well. Check the FAQ section for how to test, and set the TPS.

Code 25 -- knock sensor -- ignore this if you didn't wack the engine at the righ time durring the test

Code 34 -- This is the EGR valve did not respond durring test. could mean a couple things,
-- EGR valve is stuck open (which is why it runs bad)
-- EGR actuator is not working, and not opening at all (not making it run any worse)

Code 54 -- Intake air sensor, or VAT sensor signal high. this is the air temp sensor in the vane meter.. check the wiring.

[85bulletsvo]

The tps being out of range or no good will for sure make it run like crap.

[835.0RS]

i looked over a few things today and the tps was off. so i tried to adjust it and no matter what the voltage of .62 never changed. i took off the sensor and found out it's the wrong one because the piece that is suppose to engage in the sensor didnt fit properly. so i put a new one it and found that the orange wire was shorted to the other wires and the intake. what does the orange wire do? now the car will idle properly although sickly,and it dont die when i come to a stop anymore. however it still misses. if u pull the wires off of the middles two injectors , #3 makes no difference,#2 does some times. what would cause an injector to stop working? would this have anything to do with the fuel press. bleeding off almost instantly when i shut it off? if the injectors leak could this be why its hard to start after i have ran it?

[SVOeric]

would this have anything to do with the fuel press. bleeding off almost instantly when i shut it off? if the injectors leak could this be why its hard to start after i have ran it?

Most certainly -- and it needs to be fixed before it's driven much.

With the fuel pump like that, you are leaning out for sure, which can have bad bad bad side effects.

[835.0RS]

i know it's lean that's why the boost was set low because when i first got it i put a manual boost controller on it and played with it and anything above 12psi made no difference, it actually seemed to lose power. now that i know a little more about the car i think it's like that because of low fuel pressure and a few injectors that were questionable. i think now they quit altogether.if the injectors leak is that why i have low fuel pressure at idle(about 30psi)? is that enough to properly operate the injectors?

[SVOeric]

the injectors (most likely) aren't causing your low pressure, it's most likely the check-valve in the pump.

until you get the fuel pressure up to spec, you won't know for sure if the injectors are really bad.

[Laredo]

If you are immediately loosing fuel pressure with the key off, there are basically 3 places it can go:

1) out one or more leaking injectors

2) past the the diaphram in the pressure regulator (if this were the case you would running very rich; fouled plugs, black smoke etc)

3) back through the fuel pump - based on your other symptoms, I would check here first.

Does the orange wire have tracer color? I believe the only plain orange wire in the harness is for your oxy sensor ground. How did you check for the short to the other wires - with a meter or was it a visual observation? If it's shorted to all the component wires listed above (ECT, IAT, TPS etc) that would explain all the DTCs. Are you sure you don't have additional shorts to your injector harness?

[835.0RS]

I think the orange is solid color, no tracer. Also when grounded it caused the fuel pump to run up to pressure and shut off. Also off of idle it sort of bogs and is a slug.

[835.0RS]

today i replaced the fuel pump on the rail because i found the other one was barely working. i know have 40 psi at idle, but it runs the same. i did a compression check and found that 1 and 4 have about 130-140psi and cyl 2 has 70 psi ,cyl 3 has 60psi. none of the cylinders bleed off pressure but does this mean i have a blown head gasket or are the valves or lifters damaged?

[Laredo]

Most likely head gasket since they are adjacent cylinders. Because this is an overhead cam engine, it's pretty easy to see whats going on with the valvetrain just by pulling the cover off. Start there - it has to come off anyway to go after the head gasket. Also consoder a cylinder leakage test. Close the valves, pressurize the cylinder with compressed air and then listen/see where the air leaks are.

[NavySVO]

past the the diaphram in the pressure regulator (if this were the case you would running very rich; fouled plugs, black smoke etc)

Actually, a bad diaphram will have the opposite effect, and will lean out the engine. The boost is supposed to push down on the diaphram to close down on the fuel return so it forces the fuel to the rail. That is how fuel pressure rises with boost. The FPR vacuum hose will tell the tale on that one.

If you think you have bad injectors, then the proof will be in the oil pan. If the injectors leak by that much, the excess fuel will end up in the oil pan and cause fuel dillusion in your motor oil. Bad news for the oil and the engine.
Drop the oil and see if it smells heavily of fuel.
Also, remove the rail and leave everything hooked to it. Do some KOEO cycles to build fuel pressure (if possible) and see if the injector(s) are pooping fuel.

Fuel pump....myself, I would do it last, as you have to drop the tank, and now you are spending money.

Remember easiest to hardest, cheapest to most expensive.

Looks like you may also have a head gasket problem if you are doing the compression test correctly.

[835.0RS]

Would you please briefly outline proper procedure for cylinder pressure check. It is possible we are not doing it properly. Just want to make sure before unnecessary work is done, (hope, hope).

[NavySVO]

copied and pasted from Mike Fleming's post

No idea what fruit you're comparing to. First off what is the intake valve closing point as the cam (whatever cam it is) is installed now? Of course, you don't know. That is the #1 effect on measured cranking compression values.

Was the throttle blocked wide open for the cranking portion with a fully charged battery? All plugs out? Did you keep cranking till the pointer stopped increasing? Do you know the calibration of the gauge used? All of these will have some effect also - if the test isn't done properly, results will vary.


Quote:
sure I can adjust the timming and boost levels but why am I soo many hp numbers down from stock?

Leave boost where it is and bring the base timing up to 15. Then verify/change the cam timing.

The critical factors in getting repeatable, accurate compression numbers are: engine temp (warm is more better), cranking speed, load on engine (how smooth it spins - like all plugs out versus just one), throttle wide open, and intake valve closing point (in degrees). Funny, but it doesn't start compressing at cranking speed until the valves are all closed. I wonder what's up with that?

There is a direct relationship between CR, cam timing and measured pressure. Stolen from an old book in my library:

"Motorcycle Repair Manual", 1972, Peterson Publishing,
Library of Congress Catalog Card No. 72-85366
Page 231:

.......Nominal Compression Ratio x Intake Valve Closing (* ABDC)
================================================== ============
........8.....8.5.....9.....9.5....10...10.5...11. ..11.5..12....12.5
45...191...209...225...243...260...279...298..316. ..335...354
50...184...200...216...232...250...268...285..303. ..322...341
55...175...191...206...223...240...256...273..290. ..307...324
60...168...182...197...213...228...244...260..278. ..294...312
65...160...173...188...203...218...234...248..265. ..279...294
70...150...163...176...190...204...218...234..247. ..260...275
75...140...151...165...178...190...204...216..231. ..244...258
80...129...141...153...165...176...190...201..213. ..226...238
85...121...131...141...153...163...175...187..197. ..209...220
90...110...121...129...140...150...160...171..182. ..193...204