*Edit from the future* with the help of everyone on this forum, I figured out the issue for the long crank time and power loss.

Long crank: fuel pump check valve
Power loss: bad engine timing

*original post*
Since i bought my 88, ive been having hard-starting issues. After replacing my cold-start valve, it has gotten much better. However, it still takes a good 3-7 seconds most of the time and 10+ occasionally. I have replaced the fuel pump, fpr, fuel filter, and relay. My fpr is adjustable and it is around 40 psi at idle. I was testing to see if i had fuel pressure with the electronics on and if that pressure would hold for a little bit like its supposed to. What i found was that when i turn the electronics on, the pressure goes up to 40 psi, holds for a couple seconds, then an audible click happens and the pressure drops straight to 0. I believe the click comes from the relay but i didn't exactly make sure.

I'm hoping this issue also has something to do with my loss of power when driving. For the first 2-5 minutes of driving, it takes more throttle and rpms to get the car moving than it normally would. After 2-5 minutes of driving like that, i will feel a noticable amount of power return and the car will lunge forward. Sometimes i start the car and it drives immaculate from the get go, other times it will just be in a constand limbo of power loss no matter how long i drive. When there is a power loss i can hear a low hissing coming from the engine bay under acceleration. When it is driving great, there is no hissing under acceleration and sounds more full.

My car is automatic, straightpiped, and has the air pump delete.

Not sure if this helps, but the "D" and the "upshift" lights randomly turn on and off while the engine is on. Weather it is in park or driving

Thank you

 

I would search for vacuum leaks.

 

Before we start replacing all kinds of crap and add new variables into the equation, lets see what exactly is wrong.

Start with this. Put a gauge on the rail and turn the key. It should jump up to say 40+ psi and hold. If it doesn't, clamp off the return line at the tank and repeat test. If it doesn't hold, the issue is anywhere from behind the regulator. Probably pump and pulsator. Maybe today is your lucky day and it is the PULSATOR and that is a simple fix. Get the install kit from RACETRONIX and be done with it.

If it holds, it might be your regulator so pull the vacuum hose and see if it is bad. Why did you replace all those thing and did you reuse the pulsator?

 

ER,

easy enough to dial in where the pressure loss is from.

Do you have a fsm? If not, find a diagram of the sending and return lines from the pump.

have a friend cycle the key so that it pressurizes system while u pull the vac line from the fpr. just to erradicate possibility of a perforated diaphragm.

then, to find out if you have a hole in an injector (ha) or if its back at the pump, use two vice grips with cardboard and/or rags to protect the rubber lines and right after your friend cycles the key to pressurize (10seconds between?) clamp the send/return line.

now if your pressure drops, its either a hole in the fuel sed/return lines (which it wont be because you will reportrd seing gas on the fround) or its a hole in the injectors. (stuck open).

If your issue is in the tank, you really do not need to do anything UNLESS its causing a lack of psi while running.

—————

on to the long crank,
what i would do, is verify timing. then i would go theough the minimum idleset (cue Ak saying u need a scanner, which yes would help for sure) and if that was fine i would either buy a scanner to see what the coolant temp sensor is reading or i would simply replace the coolant temp sensor, the one under the throttle body.

 

I clamped off the return line and turned the electronics on, the psi went up to around 65, then dropped to 0. After i replaced the fuel pump a while ago, i kept the pulsator. After a couple test drives, the pump disconnected from it. Instead of securing it even more, i got rid of it. I did research on here beforehand to see if that was a good idea. Some said "just keep it the manufacturer wouldn't have put it in there if it wasn't necessary" and others said they didnt have problems after taking it off.
I replaced the parts partially out of ignorance of the car and partially out of fear of the old parts failing on me in the near future. I know its not good to just throw new parts at a car to figure out the issue, but I'm 17 and really trying my best to learn more about my car. Thank you. I will put the pulsator back and let you know the results.

 

After clamping the return line and turning the electronics on, the fuel pump engaged and caused my fuel pressure to go to around 65, i immediately clamped off the sending line also and the pressure still went to 0. The same results occured with and without the vaccum line on the fpr. There was also no gas on the ground. I did this test several times and i assumed my engine might be flooded with gas, but i timed my ignition with the few seconds that my lines are pressurized and it fired right up. I really hope this isnt my injectors

 

if you have for sure clamped the send and return line at the tank immediately following the pressurization, and if you are sure that you clamped them properly, AND you know that you are not getting gas (it would be very easy to see) past the fpr diaphragm, AND its not on the ground, there is only one place it can be going.....into the cylinders.


Which may also explain your long crank.

To be 100% sure i would redo the clamping test, you have to be quick with the clamping after the pressure is applied.

One last thing to check...Unplug the injectors from the harness and repeat the same procedure. Is it the same result? This last one is to rule out the possibility of an injector being commanded open (never heard of this but just to be sure).

If it is same result, its pointing to injectors being mechanically stuck open.

You should absolutely see wet spark plugs on some or all of the plugs. i would doubt that its all of the plugs but i do think it will be more than one.

Dont dread the injectors. Its not a huge deal. basic tools. and they are so cheap for proper injectors from fic.

 

So the hose is there in place of the pulsator? What hose did you use? It has to be submersible rated though. If not, fuel might eat it. Regular hose is good for running fuel inside. Outside has to be dry not fuel soaked. Where did you get the hose? And the pump? I wonder if it doesn't have a check valve or something to hold pressure?

 

The pump came from corvette mods and the hose came with it as well as a couple of adjustable metal hose clamps.

 

I retried the test. Apparently before, I was clamping a little too late. When i clamped the send line this time, the pressure held at around 40 psi. I took off the clamp that was on the return line and the pressure still held. I'm guessing i should check my connection at the fuel pump and sending unit. I also would've expected the pressure to drop after i released the return line and turned the key off

 

that is more like it and its what i expected. to have an injector that stuck open that it instantly goes to zero would be abnormal.

i believe there is a checkvalve in the sending unit. you should google that.

this *may* be the cause of your hard start but *only* if you are allowing the system to completely depressurize before cranking.

in other words, the fuel pump will fire again after the prime when 5psi is detected. the priming that happens when you turn the key to on, is supposed to bridge that gap. yours may be losing pressure so fast that as you crank, its not getting any fuel pressure until your cranking gets to 5psi and it triggers the pump to turn on.

There is actually a way to trigger the pump to come on by shorting two pins in the aldl.

im not sure if you simply short a-g or if you have to send 12v from the battery to the pin g on your aldl to make the pump run.

you could try this (force pump to run and provide pressure continously)and then crank. if it starts immediately, then your issue is the rapid loss of pressure and waiting for the op to sense 5psi which then triggers the fuel pump to run again after the initial prime.

 

Do you think you might install a check valve?

 

if the car still has a long crank even with the pump running continuously then you have a flood condition likely. probably the coolant temp sensor. unless you have a scanner to see what temp the ecu sees (not the same as the temp displayed on the dash) then u really dont know if the sensor is reading properly or not.

if you are not planning to invest in a “scanner” then i would go ahead and just replace the cts. it is below the tb.

 

i would now yes. but i had a car like this and it was fine in the 4 years i owned it. i was seriously penny pinching at the time. 😃

i was forced to learn clean diagnostics because i didnt have the money to be a partswapper.

there is usually a way to know beyond any doubt what the issue is if you keep peeling back the onion. but for me my time is hobby time.

 

I don't want to simply spend either. If I have to, I will. If not, I'll try to spend it wisely

Money is one thing. Aggravation at watching it sit and sit and sit, well....
​​​​​​
I don't mind tinkering. When I have to because it is occupying garage space and the wife is asking when she gets back her space, it becomes a job as opposed to a hobby.

 

I put a check valve just after the fuel pump. When i turn electronics on, the pressure goes up to around 20 and holds. It starts in 3 seconds or less every time. When i crank for a split second, the psi goes up to 40 and holds after that. While the engine is running, the psi is at 34 for some reason, but after i turn the engine off, it goes up to at least 40 and holds. I tried increasing my fuel pressure by adjusting my fpr a couple turns, but it changed nothing.

The hissing in the engine bay went down significantly and the car sounds more full. However, the power loss persists exactly as i described in the original post.
it may be worth noting that there is quite a bit of cabin vibration in lower gears. most likely from the lack of a pulsator. Oil pressure also drops like a rock at hot oil temps at idle. Into red zone. This is a recent development.

 

Something is wrong. If it holds, there is some issue that is allowing it to drain back. IIRC, someone said that not all pumps have an internal check valve. Still, what bothers me most is that you have 20 psi when you should have twice that at least. When you crank you have ignition pulse I would imagine. Not sure if it needs to see a certain amount of ignition pulse before it runs the pump. My guess is that you have a failing pump or the pulsator is leaking away pressure. When you crank and the pump keeps going, it builds up pressure to your 40 psi.

See if you can do a Wide Open Throttle. Tape the gauge to the glass, have your buddy look at it while you do a WOT run. Video it so you can see if it does drop at that time.

Yes it is worth noting. That means your imagination is running wild if the pulsator is all you change. With the fuel taking up any slack in the pump, I really doubt you can hear it and certainly not much past idle.

IDK about that. Are you sure? Check by attaching a manual gauge and see if it does that when revving. Your oil pressure loss, if real, doesn't sound good.

 

I just did a test run. I guess the fuel pressure worked itself out somehow. When i turned the electronics on after sitting all night, it went up to 40 psi and held. I posted a video on youtube so i could show y'all my results. . At 2:40 i did a wot.

My loss of power still continues as explained in my original post. Its not too noticeable driving in suburban neighborhoods, but when driving in normal traffic and highways, it is almost always happening.

I have a few suspicions after doing some research:

Fuel System- the test i posted on youtube could present issues, but I'm not knowledgeable enough to understand them quite yet other than the fact that the psi is a little on the high side for this car. The power loss could also be from faulty injector(s)
Vacuum leaks- Could also explain why power comes back to around 75% after the first few minutes of driving. I suppose i should do a smokedown test.
Torque converter- would explain the higher-than-usual rpms needed to accelerate at a normal rate.
Transmission- could be the reason my overdrive and upshift lights come on and off. Could also explain why my car hesitates to shift (lingers in a gear longer than it should) only when power loss is occurring. May be the reason cabin vibration is occurring in some gears (although the sound comes from the rear half of the car).
Timing- i have no experience with engine timing, but ive been told i should check my timing. Haven't gotten around to borrowing a timing gun
EGR- my egr light is on, but it could just be because i broke the little sensor on the egr tube. But ive seen online that a malfunctioning egr system can cause a loss of power. Could also explain why power comes back to around 75% after the first few minutes of driving (egr engaging).
TPS- my tps is at .54 volts, but even then, my engine idles around 200 rpm too high on startup, but after driving for a bit, it settles back down to 600 like it should. I have about 3 tps sensors and all work good and dont spike in voltage when i turn the throttle blade slowly.
MAF- my readings are good according to Tequilaboy. I used to have code 33, but After replacing the maf relay it went away.
Air pump check valves- I deleted my air pump assembly and tubing all the way to the check valves on the exhaust manifold. I did not cap them off. They suck in air, but dont push any exhaust out of them. Maybe this is causing turbulence and somehow makes the car have trouble accelerating.

Before anyone says i should get a scanner, i already have one. If you want to see my most recent log (recently before installing check valve in fuel line) it is on my other forum called "ALDL scan codes". tequilaboy puts them into datazap so that they are in a graph form. If requested, i can do some more.
Thank you

 

is your o2 reading lean so its flooding the engine to compensate? if your exhaust is vacuuming air in on the o2 side/driver side from the cut air injection system then it will cause major issues in fuel control.

 

I capped off the holes a few days ago and i thought it made a difference. It had 90% power on the highway and a little bit more power in general. I guess i just got lucky for a couple days because now its running like it usually does. I was finally able to do some data logs on my commute. One is in the morning (https://datazap.me/u/elijah/morning-...e?log=0&data=9) and one is in the evening (https://datazap.me/u/elijah/commute-work?log=0&data=6-9).


I believe This one is from when it was running better: https://datazap.me/u/elijah/mo-powah?log=0&data=2-9