Kevman

Hey guys, lately my car has been weird, some days it will run like a champ (Dry, hot days) and others it feels like it has 100 horsepower.. Anyway, today I was driving the girlfriend home, and I slowed down for a stop sign, it downshifted, and chugged a little bit..
The whole rest of the ride it was shaking, and vibrating, felt like it was running on 6 cylinders type of stuff It felt like it wasn't getting enough fuel.. Now, since I have owned the car, it's never started right away, takes a good 6-10 seconds whenever I want to start it up when it hasn't been run for a day.. There's a few possibilities I've thought of..
1. My fuel pump is on it's way out, 173000km on the car
2. Fuel pressure regulator is broken
3. Slipping timing chain
4. My EGR valve is toast, so to continue to drive the car, I put some RTV sealant and stuck it back on with the bolts until my new one comes in...

Lemme know, experts!

Jono4820

iTrader: (1)

Check fuel filter first (drivers side under car frame rail forward of rear tire)
Fuel pump at that age is probably bad.

Fuel pumps are easier to change than you might think.

Kevman

I was thinking fuel pump, just from the inconsistency of the problem, it's random.. I changed the fuel filter when I drained the tank last year, probably has 3000 km on it.

Kevman

Can I use a TPI fuel pump as a replacement? I wanted to put MAP Tuned port on when i do a 350 swap, anyway.

bradley23150

iTrader: (10)

The TBI pump runs just over 15psi, and the TPI pump runs like 45psi. (Don't know exact #'s)

Judging by that huge difference, no, I don't think it will work like that.

blackie

As far as the starting problem it is probably the fuel pump relay. Located on a bracket beside the brake booster. There are two that look the same one is the fuel pump the other is the fan. I have a 92 rs 305 that did the same thing.

Kevman

Doing research through old forums, I came across this.. https://www.thirdgen.org/forums/tbi/...-pump-tbi.html
Any thoughts?

I'll definatly change that relay! Never would have thought of that!

Kevman

Any ideas on the TPI Fuel pump?

Matt S iroc

tpi runs alot more pressure than tbi,it would b to much pressure for the tbi.is that what u wanna know?

Kevman

I realize it's more pressure, I'm wondering if the Fuel pressure regulator would drop it down to the proper amount. I want to put TPI on when I do a 350 swap.

I changed the EGR, and the FP relay, still runs like crap. Checked the fuel spray, with the air cleaner off was revving it up, seemed like a decent amount. I'm going to start by putting on new plug wires, mine are pretty burnt looking.

Gallileo60

My TPI pump works just fine in my L03....

campin1983

iTrader: (4)

The worry with the TPI pump has less to do with if the engine will handle the pump, as if the fuel lines will. Most of the rubber parts of your fuel system in the TBI engine probably aren't rated for the higher pressure. They may be fine for a while... possibly even a good while, but they could burst.

However, if your wanting to go TPI, those are gonna need replaced anyways. So I'd say just remember to chance the rubber lines between the pump and the motor (the return is much lower pressure)

Kevman

Which I was reading in the other one, which lines have to be changed? I have steel going from the fuel filter to the TBI unit, where is there rubber?

campin1983

iTrader: (4)

As I think about it, I don't think I've ever had a 3rd gen that didn't have some sort of fuel line repair, fuel pump replacement, etc, so I probably can't tell you for sure if/where there's rubber there. All of my cars in the past have a small piece of rubber fuel line right as it exits the tank. Not sure if that's stock or not.

If that's not stock, then just ignore me, lol. If you do have rubber line there, I'm guessing your only looking at replacing less than a foot, which isn't a big deal. I'd imagine my advice applies more to cars that have had lines patched more than anything else.

Kevman

I changed the plug wires, I had a set of Taylor 8mm's on there, 3 plug wires actually had burns through the insulation, if you bent it the right way, you could see the core.. $49 and a nightmare hour of putting them in, it starts right up!

Kevman

Update.. Drove the car for half an hour without turning it off, on the return trip I was doing about 50 km/h and it was chugging every once in a while, I think it could have something to do with my timing being too advanced..

morgsie

iTrader: (1)

The rubber lines people are talking about are the ones inside the tank. I bought a TPI (Delco) pump for my TBI Caprice and the new pump came with the proper rubber. Been running with no problems for a few months now. Driveability has improved greatly.

Kevman

I'll have to see if they still make a replacement line for that, too..

Another Update, I changed the timing, i was advanced at 14*.. I changed it to 10* and it runs a little bit better.. Another thing I noticed, I unplugged that ALDL connector for the distributor to do the timing, and the wire snapped, and it looked as though it had been broken for a while by the corrosion and black marks on the wire itself..

jay173

Check the obvius your spark plugs and wires

Kevman

Plugs looked good, wires are 3 day old Accel 8mm.

jay173

Well is it possible your new plug wires could be the cause?

Kevman

I changed them after the problem started.

built91Z28

If that wire has been broken the whole time then that could be the problem. That means you have had no timing advance at all. Just whatever the base timing is set at. Did you repair the broken wire?

Z28Smitty

You can check the fuel pressure at the shrader valve very easily. If your fuel pressure is OK I would check the resistance of the injectors. They should read around 14 -16 ohms. I had a simular problem where I had bad / intermittent injectors shorting out and causing hard start and rough running problems. Not easy to find as sometimes it would run OK.

Kevman

I crimped it for now, I was planning on doing a 350 TPI swap in the winter. It seems to run a bit better since I fixed it, too.. Odd..

I'll check this tonight, thanks!

andr3i

how much horsepower can i get out of a 305 bored over .030

bduffey723

i have an 89 rs LO3 and had the exact same problem.. slow down and it would seem like i ran out of gas, although i had a full tank.. i went to autozone bought a fuel filter put it on and ran better than before.. if u havent done that yet do that.. oh and i would say the age of the filter doesnt matter because the filter i took off i had put on 6 months earlier with some service change fuel check crap at the oil change place.. so.. check that.. ;]

Kevman

That sounds like the problem, as soon as it starts slowing down it does that, worse when it's hot.. I'll change that ASAP.

bduffey723

ya i wouldnt drive mine for over 10 minutes because it got so obnoxious.. let us knowif that does anything for u

ogg__666

check your air lines to your TBI too i had one of my air lines wasnt done up right and at low rpm my car would want to die !

BlueWrath92

iTrader: (1)

Mine did exactly this cause my plugs were not gaped right... I dunno a whole lot but mine did the exact same description, check plugs and wires..i kno u said there new...but after that I had them professionally done, and the next day I poped the hood and one of my wires was arching out...a brand new wire

Gallileo60

i thought he had a TBI, where is the shrader valve on the TBI???