My car will not start and will barely roll over when the injectors are plugged in. when they are not plugged in the car will fire and try to start but falls on its face. i would like to know how is it possible for my injectors to fire when they are not plugged in? Has anyone ever heard of this? ive been workin on this damn thing for 3 weeks now and im about to scrap it.

im having a terrible problem with this and have been chasing it all over the place but just cannot figure out what the problem is. all the injectors are good, ive had 2 different new sets in the car. I just had the motor rebuilt and the car ran fine before that.

87 tpi block
90 prom
map sense

 

It'll try to run with the injectors unplugged if the engine is flooded.
Double and triple check your firing order. You may be off on your plug wires. Don't assume that the number 1 cylinder on the dizzy vs. the manual picture are going to agree.

Also smell your oil. If you are running rich then guess where all that un-ignited gas is going.

 

into my oil/crankcase yes i know. as far as the timing goes im almost positive im fine.
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but i will double check the wires

 

ITS STARTING ON THE COLD START VALVE.. SOUNDS LIKE YOU NEED A SET OF INJECTORS. THEY ARE LEAKING FUEL INTO THE ENGINE. CALL FIC AND GET SOME BOSCH III'S

 

do what the first guy said

 

90 prom doesn't have a cold start injector.

 

the prom might not have the cold start, but the 87 tpi set up does.. is the csv still hooked up? maybe its leaking.

 

no the cold start is not hooked up and i do not need new injectors. the car now runs with injectors unplugged.. timing is right. but with injectors plugged in the car floods.

 

a good working injector will not flow unless the coil is energized to open. You are getting fuel into the engine somewhere.. the only other thing it could be is a torn diaphram in the fuel regulator and the fuel is getting in through the vac hose.. just for fun unhook the hose and see if fuel squirts out the tube on the reg. Its goto be that if the injectors are good.. hope thats it..

 

nope, wasnt that.. the injectors are firing on each cylinder like normal as if they were plugged in. ive had 3 sets of injectors in this now 1 old, 2 new

 

Hi folks
this is totally confusing - with the injectors unpluged - how can the engine run? - NO WAY unless fuel is getting in. When the injectors are unpluged, no way should fuel be getting thru them. You have to have another source for the fuel to be getting in. The injectors need an electical pulse (about 2-3Msec) to open up, they are normally closed. Find the source of the fuel or get new injectors - this is not normal or maybe our definition of the injectors being unpluged is wrong. What do you mean by the injectors are unpluged?
thanks
Bill

 

The injectors are completely unplugged... sitting in the fuel rail but no electrical hooked up to them. (the 2 wire plugs that snap on) completly unplugged. Car will fire and start to run then dies, when the injectors are plugged in car will not fire at all.

 

You should really check the resistance on all the injectors. having low resistance will cause one injector to have high amps and not let the other injectors fire, which will draw the energy from the other injectors. look into the ohms specs on your injectors..this is what happened on my 90 GTA. one injector cause it to do the same thing yours is doing. or u can try starting the car 7 injectors connected at a time, just rotate the order. have 1234567 on try to start then have 12345_78 on and try and so forth..good luck.

 

Hi folks
I think everybody is missing a basic point here -THE ENGINE SHOULD NOT RUN WITH ALL THE INJECTORS DISCONNECTED UNLESS THE INJECTORS ARE NOT CLOSED AND INJECTING FUEL OR FROM SOME OTHER SOURCE. This basic 101 of furl injector car. Find how the fuel is getting in the engine.
thanks
Bill

 

Well, let's ask a fe w more questions, just to sorta start the ball rolling

From your sig, you have a buit of modding going on...

SO...

What engine to you have?

What year intake do you have?

What computer do you have?

What year is your car?

Reason I ask is you mention '87 TPI (which has the CSI) and 90 MAP (which is SD).

So, I don't know if you're trying to run an SD setuop, on an '87 Intake, etc.

More info, is better info.

 

I'm with Bill... With no wires on the injectors, something is leaking. Look at ruptured regulator, stuck cold start or leaky injectors. Maybe extreme flood, smell your oil? Best of luck, it's frustrating.

 

87 350
87 intake
90 computer
78 camaro
map sens

and the car ran for 4 years like this untill i recently had the motor rebuilt. the motor was just rebuilt stock... nothing changed
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checked the fuel pressure regulator seems ok but replacing it anyways probably today or tomorrow, ill have an update then

 

Hi
I think you might be missing our point - no wire, no fuel. If it runs with all the injector wired disconnected, fuel is coming in some where else.
thanks
Bill

 

try running it with the fuel pump off. dry up the insides. who knows how much gas is in there.

once it runs out of gas do a fuel pressure check. then reset ur computer(remove battery ground)

also check your maf. then if it still is dumping too much gas try a wide open throttle start. i know its not the greatest thing but you might need to try to see if it will clear out
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Ive had this problem. the injectors were burnt all the way through. you could see through the other side. i wot started it and it started but then died

 

Ok update.....

New injectors, new fuel pressure regulator. The car has the correct amount of fuel pressure i have checked it with a gauge.

It made a few differences. The car does not load up anymore when the injectors are plugged in...and it seems fuel delivery is normal, the plugs arnt covered in gas when i pull them now.... although i havnt cranked it that much. the car still does not fire at all when injectors are plugged in. Now with injectors unplugged the car will start to fire but will not run (i assume its burning the unburnt fuel from when the injectors were plugged in) and soon after loads up and the motor will not turn over. Now by loading up i mean the car will not crank over. I guess it could be compared to hydrolocking... from what people have told me about hydrolocking, ive never had a car hydrolock on me so im not exactly sure im right on in my explanation.

any ideas?

 

fuel can only get into a TPI engine in the following way. 1. injectors are leaking fuel, 2. regulator diaphram is ruptured and it is going through the vac line. 3. cold start valve, (if you have one) 4. being pused in through the evac system from the polution crap cannister from the tank through the vac lines.
My suggestion would be unlock the motor. take out plugs etc. remove main vac line and start looking for fuel.

 

1. ive put 3 sets of injectors through this intake, 2 new 1 old.

2. brand new fuel regulator, all vac lines are good/no fuel

3. no cold start on this car

4. no smog can or smog stuff on this car

 

HI Maxont
Unless you are pulling our chain, no way can the engine run if you have the injectors disconnected. So we are on the same sheet of music, look at the picture - when you say the injectors are not hooked up, you mean no connector attached to the injector - Right?
thanks
Bill

 

heres another possibilaty. you might have you pressure side of the pump going to the return side of the rail. the pressure goes into the rail on the side that has no reg. the retun is after the reg.. if this is so you can pump fuel into the manifold through the vac hose. otherwise i'm stumped

 

the injectors are in the rail but there is no electrical hooked up to them
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and no im not pulling anyones chain... im very confused myself.

ive already thought of the chance i could have hooked up the lines backwards and checked on it but it looks as if the 2 have different sizes and there is only 1 way to mate each up because the other they would not fit. i would double check that again though

 

I think the lines are both the same dimensions.. or very close to it.
I put a red turkey tie around the fuel send to make sure I didn't hook up
the return instead.

Viable guess, couldn't hurt.

 

my feed/return fittings are different, completly unable to hook them up backwards

 

Yea, they probably are upon close inspection, never tried to find out
otherwise.. looked close enough for me to make one distinguishable tho!

 

haha for sure. so i have another question for everyone still keeping up on this post. i baught some new spark plug wires from a local warehouse and they were supose to be hei plug wires but they came in non hei wires. to my knowledge the only difference was the boots on them. so instead of ordering a whole new set i just had the guy that ordered them for me throw in the correct boots and off i went. so as of now im running non hei wires... could it be some possible way that non hei wires cant actually carry the correct voltage to the plug or something of that nature?

 

I am new to the forum and am trying to solve the same problem with my father-in-law's 1988 Z-28 (305 CI) TPI. With the injectors electrically plugged in, it floods the intake manifold & cylinders. Unplugging them, however, allows it to run so long as residual fuel remains.

His has the cold start valve (basically a 9th injector) which actually allows the engine to run, at idle speed, even though all other injectors are unplugged.

While it is running at idle speed he sequentially plugged in the other injectors. As more of the injectors were plugged in, it began to run rougher and rougher until it finally died.

My suspicions are 1. faulty powertrain control module; 2. faulty mass airflow sensor; or 3. other faulty sensor (e.g. MAP) or vacuum leak. This forum has helped and I will be checking for other sources, such as the suggested leaking fuel pressure regulator diaphragm.

I have verified correct ohms at injectors and correct voltage of TPS at idle position. I will be checking MAP and MAF voltages as well as fuel pressure tomorrow.

 

No. Universal sets (one's you put together yourself) come with both sets f connectors and boots.

Do a search into injector driver. I believe it's part of the ECM. It may be the cause of your problems.

 

Ok I think at this point you need to check your oil for gas getting in it and possibly change it. You probably have so much fuel in there that when you do get it to run you might ruin your bearings.

 

the 87 was maf and the 90 is mat - so if you are running a ecm for a map on a maf then you might have problems.
also someone said that your 87 had a cold start injector but the 90 did not so an ecm from 90 will not recognize it.
it would be helpful to know what you added on to your rebuild and work backwards to see if the new parts were the cause.
but the computer problem is a big one.
you would be better off getting an aftermarket ecm for the 87 so that they can talk to each other.
if you started off with the 90 chip before you did the rebuild then maybe something was changed during the rebuild to make the 87 back to spec and that messed with the computer.
there aer lots of potential problems there. so what did you have done and what did you add?