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Old 05-11-2017, 07:32 PM   #1
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305 tpi help

Hey everyone this is my first post to the board but I've been using this site ever since I got my car 6 years ago so I didn't really know where to post this so sorry in advanced if this is the wrong place.

I have a 1989 irocz with a 305 tpi and t5 the only mods are gutted air box, a 3 inch electric cutout where the cat used to be and 3 inch exhaust and the motor was rebuilt roughly 45k miles ago.

The car sat for about a year and I would start it and drive it once every month until about 4 months ago it died while at wide open throttle in third gear and I got it started but it would idle extremely rough and die when you let off the gas.

​​​​​​I'm trying to get it running again but it will only start with starting fluid and it idles extremely rough and shakes very bad. It pretty much sounds like half the engine is running. It will rev up sometimes but most of the time it bogs down and wont rev over 2500 rpms and then will die. I was getting code 42 but now it is not throwing any codes.

So far I have replaced the plugs, cap and rotor, ignition control module under the distributor, fuel filter and the car got a brand new fuel pump before I let it sit
​​​​​​
I need to get this running soon because my wife and me only have one vehicle at the moment so any help is apreiciated and thank you in advance.
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Old 05-11-2017, 08:08 PM   #2
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Re: 305 tpi help

Sounds like the fuel pressure regulator. Pull the vacuum line off of the fuel pressure regulator and check if its leaking fuel. If not then check your fuel pressure.
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Old 05-11-2017, 08:13 PM   #3
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Re: 305 tpi help

If it's bad will it have gas in the vacuum hose after trying to start it?
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Old 05-12-2017, 05:14 PM   #4
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Re: 305 tpi help

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If it's bad will it have gas in the vacuum hose after trying to start it?
Yes, but you might want to check your fuel pressure even if it is not leaking.
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Old 05-12-2017, 05:28 PM   #5
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Re: 305 tpi help

I checked the vacuum hose and it's not leaking but I forgot to mention I did check the fuel pressure a while back.
I rented a fuel presser kit from autozone and hooked it up and I turned the key to the on position and it went up a little over 40 and then the fitting that connects to the fuel rail started leaking so I tightening it back up. I tried again and the fuel pressure wouldn't go over 10 and when I tried to crank the car it stayed around 10-15psi. Don't know if I messed the tool up or it was actually reading correct.
But my wife is bringing me a new fuel pressure regulator right now so I'm about to change it and I will let you know if the problem worsens or gets better. And thank you for the reply.
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Old 05-14-2017, 02:27 PM   #6
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Re: 305 tpi help

So I replaced the fuel pressure regulator and I had to use starting fluid to get it started but it ran good for a good 30 seconds then started dying and shaking real bad. And engine code 42 came on. Any suggestions on what I should check next?
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Old 05-14-2017, 05:46 PM   #7
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Re: 305 tpi help

Well guys I unplugged the battery to let it reset and used a little starting fluid and it started right up with no codes. I let it warm up and took it for a test drive and it's running great again only bad is the back brakes started smoking a little but thanks for everyone's help!
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Old 05-17-2017, 04:28 PM   #8
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Re: 305 tpi help

You could have had some bad gas that just needed flushed out of the lines to. However, with as long as your car had bee sitting you should check and make sure the base timing is correct, the TPS is ready correctly and etc.

See, the Code 42 you got usually points to the ignition, but the control of the ignition from the computer relies on information from other sensors... this to can be influenced by battery voltage.

A lot of things to check when bringing a car back that has set. Fluid levels and quality, sensors reading properly, timing, fuel, a healthy battery, a strong alternator.... the list can go on. Another thing a lot of fuel injection guys overlook is varnish on the injectors. Just like the old days with a carb and old fuel, you can have issues with the injectors sticking (Open or closed... and open injector can show its head in fuel pressure) or having a poor spray pattern.

I would suggest checking every system for proper function and watch your gas mileage over the next few tanks to make sure you are getting what you should be. If not, something is probably wrong.
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Old 05-17-2017, 05:03 PM   #9
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Re: 305 tpi help

Hey KyleF thanks for the reply! I'm actually having problems with it again.
I unhooked the battery last night to weld a muffler on it and when I went to start it back up it would not start. I sprayed starting fluid in it and it started but again it started shaking and would not rev over 3k. I couldn't hear the fuel pump prime when I turned the key to the on position so I put a new fuel pump relay in it and it started up and drove but now it won't start at all again. It will drive once you get it strated with starting fluid but it idles very rough at 1k and will sometimes shake sometimes not.
I'm not getting any codes at all and I called the shop that replaced the fuel pump a while back and they said it could of gone bad from sitting and they will replace it for free if it is the pump.

​​So I'm going to replace the fuel filter and see if that has any effect. I remember checking the ohms on the injectors and they were 16.9, is there any other way to check if they are still good?
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Old 05-17-2017, 07:07 PM   #10
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Re: 305 tpi help

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Originally Posted by KyleF View Post
You could have had some bad gas that just needed flushed out of the lines to. However, with as long as your car had bee sitting you should check and make sure the base timing is correct, the TPS is ready correctly and etc.
So I just got home and checked the timing and its at 6* with that black and tan wire unpluged.

But here are some things I've noticed with the car.

If you start it up you have to hit the gas whenever it first fires up or it will imediately die but after you give it some gas then it will begin to idle.

Also if it's running and you turn it off and try to start it back up it will not start at all. But if you let it sit for about 10 minutes then it will start up.

any ideas what that means?
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Old 05-17-2017, 07:54 PM   #11
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Re: 305 tpi help

You might have more than one issue. Throttle shaft worn and sticking or iac not working.
The hot restart could be a icm or pu coil .
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Old 05-18-2017, 09:21 AM   #12
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Re: 305 tpi help

I agree, need to check your IAC. You should not have to give a fuel injected motor gas at start up or keep running. This almost seems like weak fueling. If you have a scanner, at idle, you should see counts for the IAC, if you do not, then you probably have an issue with the throttle blades sticking open resulting in a lean condition that the computer won't compensate for at idle.

I would run a leak down test on the fuel system. Hook the gage up, let the pump prime, and then turn the key off. Pressure sure hold steady with minimal decay over time. It won't permanently hold, but if all the pressure is gone in 30 seconds you have one or more injectors hanging open.

I would also suggest running a high quality fuel injector cleaner through the tank. Some built up varnish can be removed this way. If you have leak down issues you will have to pull them and clean them, or send them out for service. Poor spray patter can explain why you have to open the throttle... get the air moving. Once it warms up the fuel burns better.

You can remove you ignition control module and coil and have them tested. Usually issues arising only when the engine is warm points to the electrical components in the ignition.

FWIW the last TPI I had that required using the gas pedal to rev the motor to prevent stalling ended up being the fuel pump. I used to work at a parts store some 20 years ago. What I learned was new parts also fail. You would be better off having a starter/alternator/fuel pumps... part with moving internals that had been used for 6 months. So do not look past your fuel pump. Something I have done it the past is run the hose of the fuel pressure kit up through the cowl area of the hood and lay the gage on the glass where I can see it. Take it for a short drive and when you open the throttle and get in the upper rpms if the pressure drops your pump is weak and can't keep the rail pressurized at higher flow rates.
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Old 05-18-2017, 05:18 PM   #13
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Re: 305 tpi help

Quote:
Originally Posted by KyleF View Post
I would also suggest running a high quality fuel injector cleaner through the tank. Some built up varnish can be removed this way. If you have leak down issues you will have to pull them and clean them, or send them out for service. Poor spray patter can explain why you have to open the throttle... get the air moving. Once it warms up the fuel burns better.
Hey thanks for the reply again and I was messing with the car again earlier before I read this. I decided to look at the injectors again and I noticed with it idling 3 of he injectors (one on the driver and two on the passenger side) were not ticking as loud as the rest and when you put your finger on them you could barely feel them tick. So I pulled out the multimeter and checked one of them and it was reading 3.8 ohms so I figured it was safe to say the other two are going to be bad as well.

Could 3 bad injectors be causing these symptoms?

also I was looking at replacement injectors and found the Bosch III from South Bay and I've read a lot of good reviews on this site about them and for $155 for a set of 8 I figured why not replace all of them if three are bad.
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Old 05-18-2017, 06:14 PM   #14
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Re: 305 tpi help

Yes, 3 injectors not opening correctly or not closing would definitely cause running issues.
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Old 05-18-2017, 06:23 PM   #15
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Re: 305 tpi help

Well I'm going to order them next pay check and install them and see if this fixes it. Thank you for all your help and I will definitely keep you posted after they are installed.
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Old 05-18-2017, 06:25 PM   #16
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Re: 305 tpi help

Fuel injectors don't usually go bad. They're rated for a long, long life. If you do decide to change them out, do all of them so you're not going back in to do it again. Also, fuel in the pressure regulator (FPR) vacuum line means the FPR is bad. Another way to check is with the car running, check the fuel pressure. Then with the car still on, remove the FPR vacuum line from the intake; the fuel pressure should go up. If it doesn't it indicates a bad or ruptured FPR diaghram, it just hasn't started leaking yet. Just FYI. You got great answers from the rest of the members here.
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Old 05-18-2017, 06:45 PM   #17
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Re: 305 tpi help

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Originally Posted by Brianb4 View Post
Fuel injectors don't usually go bad. They're rated for a long, long life. If you do decide to change them out, do all of them so you're not going back in to do it again. Also, fuel in the pressure regulator (FPR) vacuum line means the FPR is bad. Another way to check is with the car running, check the fuel pressure. Then with the car still on, remove the FPR vacuum line from the intake; the fuel pressure should go up. If it doesn't it indicates a bad or ruptured FPR diaghram, it just hasn't started leaking yet. Just FYI. You got great answers from the rest of the members here.
​​​​​​
Hey Brian thanks for the reply!

I've already replaced the fuel pressure regulator and it had no change with the symptoms. But the shop that rebuilt my engine a while back said I had a couple bad injectors and replaced them with used ones so I'm thinking they weren't the best quality because the shop wasnt very good. I went with the them because I had a tight budget but I had multiple issues after they rebuilt it including them frying my computer somehow and my car not running when they gave it back to me after they said it was good to go.

And just like you said I might as well replace all of the injectors while I have everything apart so I'm planning on just replacing all of them with those Bosch III's from South Bay Injectors. But thank you for the reply and if you have any tips or tricks to make replacing them easier please tell me lol this will be my first time ever replacing injectors.
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Old 05-18-2017, 07:01 PM   #18
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Re: 305 tpi help

Fuel injectors go bad often from sitting. Had a set of Accel injectors go bad after sitting in a garage for 3 years. 3 of them just froze up.

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