Hey guys,

ive just been reading through a few threads on here and now im thinking my cars injectors maybe bad.

The car had been stood from April to August while i fitted some hooker headers, fuel filter and removed all the AC and emissions stuff, all of this was disconnected anyway it just hadnt been taken out, then the car went for a stainless exhaust made. I also fitted new plugs and 8mm leads.

I put the car back on the road at the start of september and for a while it felt great, louder and quicker ! then gradually it felt like it was hesitating now and then but nothing to really worry about.

now over the past 2 weeks its started stalling when going from park to reverse or drive, not all of the time, just sometimes, but once i start driving it, it gets really bad, now its constantly misfiring and stalling at junctions, basically it just runs like crap.

i pulled a few plugs this morning and they were all black and had a bit of wetness around them too.

i replaced the ignition module yesterday too before checking the plugs and its made no difference, im just wondering if the injectors are on their last legs and are over fueling ? ive never once checked the injectors so doing this OHM test hot and cold im not sure where to start

 

This sounds like the same issues I'm having with my 85 IROC 305 TPI. I'm thinking the same... My plugs, wires, module, cap and rotor are less that 6 months old. It will idle bad and has loss of power on acceleration. If I step on it, it will eventually accelerate, but not after some horrible hesitations.

Anyine got any suggestions for us?? what is an easy way to test the injectors?

 

im getting different answers from different forums too which isnt helping, lol. Im really starting to get sick of the whole car as its just one thing after another, i spend more time fixing things than driving it.

i checked my cap and rotor when i replaced the module yesterday and they looked fine, i still gave them both a clean up. o2 sensor is new also

 

hey guys, can someone tell me how i check the ohm rating of the injectors, ive never touched them before so i dont know what im doing, do i pull out that metal clip to expose a wire to put the voltmeter on or something ?

http://www.flickr.com/photos/43070182@N04/6250092974/http://www.flickr.com/photos/43070182@N04/6250092974/ by http://www.flickr.com/people/43070182@N04/, on Flickr

 

. test injectors. you may have a bad/heat damaged plug wire, really, common with headers.

 

thanks mate, looks easy enough to do. My leads are new and i made sure they were as far away from the headers as possible, ive checked them all and they all look fine, no discolouring or anything

 

Don't give up..it usually all works out in the long run. Check the ohm readings both hot and cold...when checking hot, try to let the engine run for a few min. At that point you can also pull the plugs, if you have wet cylinders you have leaky injectors. Any ohm readings less than 12 indicates that your coils are beginning to fail. You can also use a noid light to see if they are pulsing. Did you ever change your fuel filter? Clean out your fuel system?

www.southbayfuelinjectors.com
516-492-6504

 

yeah i changed the fuel filter back in march this year, and i put redex injector cleaner in the tank twice a year just to help.

i hope its the injectors, ive also been told even if the ohm rating seems ok on them they still might be leaking anyway and need changed.

 

this is true, but again the easiest way to tell if they are leaking is to pull the plugs and check for wet cylinders. If you really want answers you can send the injectors to us, we will put them on the bench and check them for you ..... no charge.

 

thats very kind of you mate thanks, only thing is im in the UK so it would be a bit of a headache, if i do decide to get new injectors then i'll be coming to you guys if your ok posting to England ?.

Ive just been out there to do the ohm test, my voltmeter is just a basic one so i had to try to dial in a few positions on the ohm setting before i got anything, every single injector came back at 16, then i ran the engine for 10 minutes and done it again, still all 16 ? i didnt pull any of the plugs today, but i did yesterday and they were all black and a bit wet, and i hadnt started the car for over a week, i put them in at the start of september, so they havnt even been in the engine 2 months, this is how they looked yesterday

http://www.flickr.com/photos/43070182@N04/6249584596/http://www.flickr.com/photos/43070182@N04/6249584596/ by http://www.flickr.com/people/43070182@N04/, on Flickr

I also remembered to pull the error codes, ive got a code 22 and 36, ive had the 36 for ages so im not bothered about that one yet, the 22 however is helpful, bad TPS or a problem with the fuel cutoff circuit ?

 

I was referring to spark plug wires.

 

so am i, i put new 8mm superstocks on, i cut them to fit so they werent close to the headers

 

sorry, didn't realize that you are in the UK...that would be a littel inconvenient wouldn't it!
We do offer international shipping, so if we can help you in any way please contact us.


www.southbayfuelinjectors.com
516-492-6504

 

will do, thanks mate. ive heard the bosch 3's are the best ones to get for the 305 ?

thats if it is the injectors anyway, im not sure if this code 22 related to my problem or not

 

You can check the top two wires of the TPS connector (when connected to the TPS), it should be .54V. Even a small deviation from this will cause drive-ability issues.

I was able to test my injectors for leaks by removing the plenum and a runner. Then remove the fuel rail retaining bolts and gently lift the fuel rail (including the injectors). Place clean paper towels under the injectors (making sure the injectors re resting on the paper towels). Energize the fuel pump to pressurize the fuel rail. Check for obvious leaks under the injectors, the paper towels should help in this. You can check the CSI in a similar fashion. Loosen the retaining nut for the CSI feed tube. Rotate the CSI and tube, upward pivoting at the fuel rail fitting.

I had 4 of 8 leaking injectors that all ohmed out ok. I never would have found this without tearing it apart. It took me one afternoon to do this.

Hope this helps.

 

thanks a lot skibum! i think i will sort the TPS, clean the plugs, clear the error codes and see what its like, and if it goes back to the way it was then its new injector time.

in other words, try the free fixes first

 

Speaking of free fixes, Ill just clarify what southbay08 said earlier.

This may also help darrlee

gta_knight, since all your injectors came back at 16, and you covered pretty much all of your ignition, try this. Unplug one injector connector and plug a noid light in and start the engine. It should blink. If it doesnt, or intermittent, the injector connector is bad.

My 85 TPI had 2 with damaged pins internally which wernt sliding onto the injector pins, one with broken wires inside the rubber "boot" and 2 that were intermittent. Thats 5 all together. After changing plugs, wires, cap, rotor, fuel injectors, and 2 tpi plenum gasket sets, it was the 5 bad connectors to the injectors all along.

To make a long story short....check them.

 

double post...

 

I like the free fixes as well.

You should also check the fuel pressure, it should be 42-47 when not at idle.

Pull the vacuum line that goes to the fuel pressure regulator. Pressure regulator is at the back of the fuel rail on the pass side. If the inside of the vacuum hose smells like fuel, the regulator diaphragm may be leaking.

Hope this helps.

 

thanks guys, all info greatly appreciated as ive never dabbled with the fuel system ever apart from changing the fuel filter, lol. If i unplug an injector and start the engine will that make it run worse ? guess its only for a few seconds to check a connection

looks like ive got plenty of things to check at the weekend depending on the weather, it sucks not having a garage

 

Yes it will run worse, but that also shows you the connector you just took off is working.

Let us know what you find.

 

hey guys, its getting really cold and dark very early here in England so all i managed to do tonight was check the TPS.

the voltage reading was fluctuating constantly, closed throttle it was jumping between 0.09 and 0.19, so i loosened the screws and rotated it upward as far as possible and the most i could get out of it was 0.37, but it was still jumping all over the place anyway. Anywhere from that way back down to 0.08 and everything in between.

i opened the throttle to the max and the highest i saw it get was 3.97 i think, but again it was jumping all over the place, it was going from around 1.60 upto the 3.97 and everything inbetween too, soooooooooo, im guessing my TPS is bad !?!

 

Yep, bad TPS. Glad you found it; unfortunately they are kinda pricey. When they operate properly, there is a smooth transition from .54v (idle) to <5v (WOT), it should never "jump."

Good luck.

 

yeah im having a look now, its not so much buying the part its the crazy postage prices to the UK for a tiny little thing !

im guessing the AC delco one is the best choice, theres much cheaper ones but ive heard bad things about standard motor products stuff, not sure about Wells ? theres is sort of in the middle

 

found a place on ebay that sells AC delco TPS's for much cheaper than others, new TPS is on the way

by time i get all of my spark plugs out to clean it might be here i need one of those go through socket things, damn headers !

 

Lots of good info. Will check these items on mine next weekend hopefully.

I'm thinking it's the injectors, but hoping for an easier fix.

 

OK, got a chance to check a few things today. All the connections look good (have not checked the Ohms yet though). My TPS is at .55v and runs smooth through to WOT (maxed at about 4.49v). I will adjust it to .54v, but the manual states it can be in the range of .54v - .62v?? So I don't think thats it.

I want to check the fuel pressure, but don't have anything to connect to the pressure connection on the fuel rail. However I did push the pin (looks like a tire valve) and with the ignition off it had no pressure at all. I turned the ignition on and I expected it to be under a lot of pressure but the fuel just kinda leaked out when I depressed the valve. I turned the ignition off and pushed the valve in again and it was back to no pressure behind it. I would think that there would still be some "residual" pressure immediately after turning the ignition off?? Could this be from injectors leaking? Or a bad fuel pressure regulator? Or even a bad fuel pump? (I believe the fuel pump was replaced not long before I bought the car last December)

I guess I need to go get a fuel pressure gauge to check it properly.

Does anyone know if the fuel rail should still have some resdiual pressure immediately after turning the ignition off?

 

It should spray like hell out of the shrader valve on the fuel rail, yes.

 

I figured it should, that's what made me decide to start tearing it apart. I stripped it down to the injectors today and the intake was soaked in gas. The injectors were in bad shape and according to the stampings on them, they appear to be the original injectors from 85!

So new injectors are needed. I'm planning to change the fuel pressure regulator and EGR while I have it all apart.

What is the "9th" looking injector that came off the drivers side of the intake?? will this be included when I order some injectors? Is it an additional regulatror??

Any other suggestions of items that should be replced while I have the ports and fuel rails off?