Don?t hit rev limiter.

[Young1]

1990 car. 1991 engine with correct 1991 Haibeck chip. My project idles well and has great drivability. It won?t hit rev limiter in first and second gear. It flattens at 5,000, gets to 6,500 and stops. TPS is .58 at idle. FSM limit is .59. Fuel system pressures are Ok. Secondaries are working I can feel the kick at around 3,500. Vacuum system has been thoroughly checked and tested. Throttle blades visually open 100 percent and air cleaner is new. I have no codes on scanner and no check engine light. It is not making that strong pull of power to rev limiter. What other parameters should I check? Need help. I have a buyer for the car.

[tccrab]

Maybe your accordion air duct is collapsing and restricting your air flow.
If you're sure of fuel and spark, then it's gotta be air.

Crabs

[Young1]

I have duct supports inside it and I ran it without air cleaner or accordian also. Hmm

[efnfast]

I'm thinking the secondaries are not opening.

[tccrab]

I'm thinking the secondaries are not opening.
Or the butterflies are opening, but the secondary injectors aren't squirting fuel.
It's two different operations.


Kinda makes sense, you feel the kick at 3.5k as the butterflies open and extra air is let into the heads, then as RPMs climb the engine goes lean because there's no extra fuel.


Crabs

[secondchance]

I?m with collapsing intake duct.

[precast1]

Did you get it figured out? Sounds like maybe not enough fuel? Getting closer to PA.

Sent from my SM-G986U using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[Young1]

Last night I found an obstruction in fuel pressure line. Blew that out and replaced hose assembly. No difference. Tccrab description is exact. It has air to make higher rpm but not fuel. I spliced the power key wires together. Full power light came on but no full power. I removed 91MY Haibeck prom and installed a 90MY SGC prom. It ran hard and fast full power to rev limiter! Once. Next time I tried check engine light came on which means it threw a code. I will check out that code tomorrow. Making progress. I least I know it WILL make full power. Also I need to diagnose the non working cruise control.

[XfireZ51]

Last night I found an obstruction in fuel pressure line. Blew that out and replaced hose assembly. No difference. Tccrab description is exact. It has air to make higher rpm but not fuel. I spliced the power key wires together. Full power light came on but no full power. I removed 91MY Haibeck prom and installed a 90MY SGC prom. It ran hard and fast full power to rev limiter! Once. Next time I tried check engine light came on which means it threw a code. I will check out that code tomorrow. Making progress. I least I know it WILL make full power. Also I need to diagnose the non working cruise control.

I?ll bet its a code 61. Lean condition.

[fastpace]

Last night I found an obstruction in fuel pressure line. Blew that out and replaced hose assembly. No difference. Tccrab description is exact. It has air to make higher rpm but not fuel. I spliced the power key wires together. Full power light came on but no full power. I removed 91MY Haibeck prom and installed a 90MY SGC prom. It ran hard and fast full power to rev limiter! Once. Next time I tried check engine light came on which means it threw a code. I will check out that code tomorrow. Making progress. I least I know it WILL make full power. Also I need to diagnose the non working cruise control.

On the cruise control front there's some good threads on the troubleshooting. Mine was a hole had worn in the vacuum line running to the cruise diaphragm on the drivers side. There's also a vacuum line that runs to a clutch pedal switch too.

[aafc]

Hi Steve,
Have you checked the fuel pump current draw? I believe its 8-9 amp draw
with both pumps. You may have a weak fuel pump. Next time connect a mechanical fuel pressure regulator and take it for a test run.
John

[Young1]

Fuel pumps replaced. they pull 8 amps together. FPR replaced so have perfect 50-51 psi. Accordian does not collapse. I have four support hoops inside it. It actually bulges out. Filter is new ACDelco. She gave a 55 code. Fuel lean monitor per FSM. If I take off the air filter assembly and accordion she runs hard to rev limiter. With filter assembly throws code and is a dog.

I ordered a line and coupler to extend my fuel pressure gauge up to the windshield. Amazon should deliver it tomorrow. Maybe I have a defective new fuel pump or FPR? A test run with a gauge is a good idea. My gut tells me fuel delivery. Either mechanical problem or ECM problem. My secondary injectors all tested 12 OHms perfect on the bench. I need to test them from the ECM. Maybe have bad wiring. But it did run strong when it did run. Sheesh

Cruise control all lines and tank hold vacuum with tester. There is vacuum at servo when running. I replaced the 3 way vacuum valve under plenum already. I removed the clutch and brake vacuum and electrical switches and bench tested all good. The line from servo to vacuum switch holds vacuum. The 3 amp fuse is good and there is power at the fuse. Everything is connected above driver hush panel.

Keep ideas coming team.

[XfireZ51]

You need to ohm ALL injectors after about a 30min heat soak. On the bench is a good start, but need to see if heat affects performance of injectors. It can and does. What injectors are they BTW?
Also, have u checked FP with FPR vacuum line connected and then disconnected?

MALF code 55 is an ECM ERROR according to the OBD1 MALF code list.

https://mechanicbase.com/trouble-code/obd1-codes/

[Young1]

Car won?t start. Checked fuel pressure. 20 psi. Primary pump pulls 3 amps. Secondary pump .8 amps. Pumps bad, check valve in pump bad, pressure leak or all three with my luck. Appears I have a new part failure now. Saga continues.

55 code per FSM is fuel lean monitor.

[DRM500RUBYZR-1]

Car won?t start. Checked fuel pressure. 20 psi. Primary pump pulls 3 amps. Secondary pump .8 amps. Pumps bad, check valve in pump bad, pressure leak or all three with my luck. Appears I have a new part failure now. Saga continues.

55 code per FSM is fuel lean monitor.

Or, something came loose.
While pumps do indeed fail, check ALL of the hose connections on the pumps, as well as the hoses and connectors.

I remain puzzled by the line in your earlier post that stated all was fine with the air duct filter etc. removed.

Investigate, diagnose and correct the lack of consistent fuel pressure first.
Then repeat your attempt for full acceleration with and without the air box setup to see if you experience that again.

Keep us posted of your progress.
You will get it.
:cheers:
Marty

[XfireZ51]

From the Registry ALDL Fault code thread

http://zr1.net/forum/showthread.php?t=25660

[Young1]

Yesterday I added fuel to the tank, took it out and it ran strong three times and then threw a code and went flat. I rechecked the pumps. Each pump individually gives 4 Amp and 51 psi. My son encourages me to go out and try it again dad. So we tape the fuel pressure gauge to the windshield I hook up my scanner so he can watch the O2 values. It runs like a champ hits the Rev limiter in three gears has a consistent 50 psi and O2 values of 700 to 800 at wide open. All is well but I don?t know why. Possibly it had some trapped air?

[bowtiguy]

Did you change out the "Y" adaptor AND new submersible fuel lines when you did the pumps? I had one car that had a cracked platic "Y" and another with factory fuel lines that split w/ only 8300 miles on the clock.

[Young1]

I have on other cars but not this time. All yet quite flexible and plastic Y was good. Holds fuel pressure a good long time after engine shut down. That submersible fuel line is expensive too. I also use high pressure clamps and not the screw type.

[aafc]

Steve,
If you have not replaced your submersible fuel hose you can both from rock auto. Gates 5/16 in x 1 ft submersible fuel hose part # 27093 and 3/8 in x 1 ft
submersible fuel hose part # 27037.
John