My younger brother just bought the car today. We got it home and I helped him change the fuel filter, cap, rotor, plugs and wires. Car still does the same thing.

It won't start unless you pump it as you turn it over, and you have to keep lightly pumping it to keep it running. If you pump it harder and faster you can get it up to about 2500 RPM but that's it. If you hold it down it will die. It also won't Idle at all. We took off the air filter assembly and watched the injectors. I don't know what is to little and to much. It was a realitivley wide cone and when you give it more gas they tend to put out more fuel, BUT they shoot out a bigger cone AND they FLOW/dribble fuel out the middle sorta when you give it more. To the best of my knowldege they should never flow and dribble. but they seem to be lettign out a decent amount of gas. Once again I don't know what is to little/to much

So, What do you think?

My 4 Ideas are that it's the fuel pump, or the fuel injectors. We Have a new fuel pump because the guy who sold it to us thought that's what it was so he through one in (parts them out) My dad thinks it may be the catlytic converter pluging stuff up, but There is pretty good amounts of air coming out the tailpipes, so I half way ruled this out. The last is that maybe the timing chain jumped a tooth, But it doesn't backfire out he pipe or manifold, so I halfway ruled this out too. :edit: could the coil have anything to do with it

I don't want to replace the fuel pump and figure out that that's not it, so any other ideas?

It Is NOT plug routing either (18436572) and I can't check the timing cause every time I pump it to keep it running the computer messes with the timing and the stupid mark jumps everywhere.

 

Check the catalitic convertor. Mine did exactly that if you watch the tb when you have it around 2000-2500 you can see it almoat looks like gas is being shot back out.

 

first thing i would check is the fuel pressure.... after that, id look at the exhaust.

 

How do you check fuel pressure on TBI?

Cat is getting cut today.

Anything else?

 

even if the cat is toast, it should idle ok.

i would give the fuel system a good check, then do a good tune up, new plugs/wires/cap/rotor, and check it all out for vacume leaks. also check the timing on it. pretty much do all the normal maintance stuff, since you don't know when that was last done.

 

that's what I thought about the cat, but I wasn't sure. Has anyone else had a problem like this and have it be the cat?

9177: did your's idle at all?

Already put new cap, wires, plugs, and rotor on. Didn't bother to check vacuum, It might be some of the problem but It couldn't be making it run this bad I know the major ones are all hooked up. And like the timing you have to pump it to keep it running which makes the timing and vacuum totally eratic.

Isn't the timing some how computer controlled? I thought I read in some car mag that you can sorta set the base timing but the computer puts it where it wants it as soon as you give it gas. Can can I just back it up like With HEI? heck can I just toss hei in it?

 

yes it is computure controlled, but you need the base set properly. there is a timing 101 article somewhere in the forum, that explains it. if you base timing is off, it throughs the whole timing curve off. it will also effect vacume at idle. and of course, vacume effects fueling (thats the way our FI works).

 

you got it... theres a plug on the passenger side fender.. one wire weatherpack connector... (brown or tan if i recall correctly..)

with the car off, unplug it... this will remove the computers advance. then set the car to the proper base timing.. it should be on a stickerunderhood... mine was 0* but ive read on here about others being 6 or somthing like that.

once the base timing is set, reconnect the wire and thats it.

 

oh, to check the TBI pressure, theres a number of ways.

you can get a TBI fuel pressure gauge..

you can tap a gauge anywhere in the line between the pump and the TBI... some people cut the rubber feed line and splice in a gauge connector there... others connect it to the hardline near the fuel filter...

 

Everyone already pretty much summed it up but i second checking the feed line fuel pressure. When my pump went south I still had a nice cone shape spray and i figured my pump was okay. A quick check showed only 6psi. Enough to get it to sputter but not enough to keep it running. If you find that is the culprit I would look at an atermarket pump.

 

Get a can of quick start and run the engine with all the breather assembly hooked up tight. Have your bro stand on the gas a little if thats what it takes to keep it running. Spray the quickstart all around the base of the TBI unit. If the engine changes RPM either up or down you know you have a vacuum leak at the throttle body. If that produces nothing then with the engine runnng spray all around every vacuum hose and connection. Listen for the same rpm change and you will know if this is your culprit. Many times you can't see a vacuum leak but it sure sounds like one to me. Besides this is a real low cost fast check that will either rule out a leak with cetainty or find the exact source of your problem.

 

A vacum leak will cause the car to idle very high and not settle down. It will in most cases not stall out the car.

 

Hey man hows it going? Never chatted before. Anyways I have a TBI GM pick up and it had a vacuum leak under the throttle body that caused it to stall out. Not quite as bad as what this fellow is claiming but it did stall especially when cold. I don't see how this is bad advice especially when you factor in that this is about a 2 min check and all you need to use is about $.50 worth of quick start. I don't mean to knock you other guys or any disrespect but i feel many times the simple things get overlooked. Maybe its a vacuum leak combined with something else but regardless the thing is not going to run worth a pinch of hawsenfeffer if there is a leak and I know I would start by checking that and go from there

 

You missed my "in most cases" dissclaimer Your advice is sound indeed and it is a quick check. You had a rare situation where a vauum leak caused your car to stall out. Therefore, it seems plausable but most likely not the case. None the less, a few second diagnosis can out rule that problem such as you mentioned.

 

At first it wouldn't idle at all. With mine everything that was inside of the cat fell apart and there was a huge chunk of crap blocking the flow.

 

Yeah I did miss the disclaimer You know even though in my case it was a vacuum leak it was bloody murder to try and fix that farfanootin thing. The winters up here can get pretty harsh and I bought this truck from Timmins which is WAY North. The body is solid cause it was oil sprayed so much but the engine was coroded quite badly... in fact there is absolutely no paint left on the engine or air breather. Anyways my point is that one of the bolts that hold the throttle body on broke off in the intake due to corrosion and no extractor would remove it either. I ended up drilling the intake out and tapping it 1/2" and drilled and tapped the center of a 1/2" bolt to 1/4" and threaded the bolt into the intake. Then I cut it off flush and bolted it back together. Of course this was in the middle of winter and i started to fix what was "suposed" to be a fifteen minute gasket change on a Sunday afternoon. I got home around 1am after all the grief

 

It was the fuel pressure. Put a new pump in and it fired right up.

Man I hate that job. Had to take the tank out of my bird when I switched it to carb. It was a lot easier this time knowing what I'm doing, but it still sucks.

Thanks guys.

P.S. I got it running for him right before I had to go to work so I couldn't check the vacuum or set the timing, But we did take it for a spin around the block and it ran pretty good for a little 305.
HOWEVER, it has a HORRIBLE miss at like 1500-2000, but only at part throttle. If you mash it, it'll run good all the way to red where it hits second and spins the rear wheels (10.5" wide, thanks B&M ) And it runs good at idle, just that little window at probably 1/4 throttle. Any ideas on this one? timing maybe?

 

What is your timing at right now? I would check that if you played with it to much. Glad you have her runnin again.

 

Looks like you hit the nail on the head Shifty

 

all right, well I timed it today. The hood says to set the base at 0* but it didn't idle very good and still ran like crap, so i tried it at 10* and it still did it. Ended up leaving it at 0* cause that's were it's supposed to be.

It's pulling 17" of vacuum at 600ish rpm. Whats normal for TBI 305's ? I'm guessing around 19-20", but I'd consider 17" pretty darn good for any of my engines but I don't know about a stock one.

SES light is on pretty much any time you aren't at idle, but sometimes it takes a few minutes to kick on. I think if it sits and idles for a while it kicks off. Where can I get a cheap code scanner thing to diagnose it?

This is my first time really working on a fuel injection system and I really don't know to much about diagnosing them. From the way the engine runs (misses and ocassionally pops or slightly backfires) It TOTALLY feels like the computer isn't pulling anywhere near enough advance. (feels like a carbed car locked down at about 10* btdc) BUT that is only between 1/4 to 7/8 throttle BELOW 3000 rpm. and at 1500-2500 it runs like crap even at full throttle.

I noticed the intake has some gasket sealer that is not factory at all around the front of the intake. I'm begging to wonder if it has a cam in it??? it does have a little tiny lope. maybe? IT has a TH-350 W/shiftkit and I think different rear end gears, maybe someone stabed ina whole different motor (350???)

Thanks in advance

 

the code may be related to the ESC, and you may not be getting the proper advance.

there is a tech article on the site for scaning codes.

here is the good news! you can do it with a paperclip!!!!

 

Did you unplug the EST as you set the timing. A poorly timed TBI car can lope pretty good.

 

yeah I unplugged the little tan wire W/ black stripe I watched with the timing light when i did it and it dropped about 15*

Where's this article and stuff about a paper clip???

Can i just put HEI in it?

 

You already have an HEI set-up. Read towards the bottom of this thread and read Tricksters posts. It will tell you the paper clip method.

https://www.thirdgen.org/techbb2/sho...hreadid=250216

 

gonna go try right now, Thanks

Won't it reset after I turn it off? Gonna go try anyway

 

it will store the code. to erase the code, you have to disconnect the battery. (or the ECU like i do)

 

Codes 24 33 42 54

24 - vehicle speed circuit. It has a turbo 350 and the speedo isn't hooked up. So this code makes sense.

33 - high voltage/low vacuum at MAF/MAP sensor, could have something to do with it where is the MAF/MAP on these cars? We put an open element on it and since this is common I'm assuming these cars have MAP???

42 - Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit - this sounds more like it, how do i fix it??? haha

54 - Low voltage at fuel pump OR Low voltage at Fuel pump relay OR Output failure at quad driver module. What is a quad driver module and what does low fuel pump/relay voltage actually mean?

hmmm. maybe it's time for a new topic

 

hmmm. I was just looking at the timing 101 post. Are all the little EST wires always in that same harness? The one i unhooked was coming out of the fatter harness right above the heater box thing.

Nevermind, I just went and checked and that's the only tan/black wire. Any idea on the diagnostic codes?

 

1) MAP - Check this out, if the vacume came off, you will get this code. this will also cause the car to idle very poorly.

2) ESC, probably not really a code, this is most likely here from when you timed the car, disconnect your battery for a few minutes, then start the car again, this should go away. IF it doesn't, you need to start looking at the spark componets, knock sensor, ect.

3) This is pretty easy to check, check the voltage wtih a DVOM at the fuel pump relay.

 

I found a vacuum line off when we timed it, but i haven't unhooked the battery since then. So both codes may mean nothing.

Is there any way to drop in an older HEI that is not computer controlled? I am almost possitive it is timing. And I have a few HEI's laying around. Can it be done?

And could low voltage at the fuel pump relay have anything to do with the way it is running? What exactly does low voltage at the really mean anyway?

 

screw it i think it has a rod knocking a little too. That would make the motor pull timing and that would make sense as to why it runs best at WOT (open loop) Is there a code for knock sensor?

I want to keep it TBI, and so does my bro but we're thinking 307 from a 69 chevelle FACTORY rated at 200HP W/ some hedders, a torquer II intake, edelbrock carb, and proform distibutor kit, maybe a small energizer cam. Probably 225-250 HP Lot better than 145 that doesn't run right.

*note 307 made 200 HP W/ 500 cfm 2 barrel....hmmmm sounds familiar. Then I could try burning chips!!! (way different cam and heads even when stock)

If only I could get these bugs worked out....*

 

Don't waste your time with that 307... They used different horsepower ratings back then that gave the impression of higher power. In 1973 they started using SAE net horsepower ratings which are still used today. The 307 shares the same stroke as a 327 with a choked down bore so they don't produce much torque and are not a good choice for performance.

 

It is just easier to stick with what you have. Your prom settings will determine the total advance. I would just re-time the car now that you have the MAP plugged back in.

 

I don't think it was the MAP But maybe, It went from the back of the TB up to a sensor thing mounted right by the ac box thing. Any way. I had it plugged back in when I set the timing. I found it when I took the Air cleaner off to get to the distributor.

Why is it easier to stick with what I have? Would it still run? I know dropping the distributor in wouldn't be that hard I'm just worried about the computer not reading anything and not firing the injectors.

Finally, My brother wants the 307 cause he wants decent mileage (i have a 350 with less than 10,000 on it that i offered) And he wants something different, And really they aren't that bad of a little motor, They fall directly between the "legandary" 302 and the "unwanted" 305.

Like you said they have a 3.25 stroke, but they also have a 3.875 bore which is a whole 1/8 inch more than the 305. In my opinion a 307 isn't as good as a 350, 327, or 302, but it IS better than a 305. Not to mention that with that short stroke and slightly smaller pistons (than a 350) he'll be able to run this thing at 6000 rpm all day

 

not to bust your bubble but a 305 has a longer stroke than a 307. 305's and 350's share the same crank. The 307 is a much worse motor than a 305. I'm not saying i have a lot of motor knowledge. i've built a couple small blocks and a big block. I don't think I've ever seen a chevrolet with a 307 I thought that was an olds thing? i'm probably wrong though.

As far as the 305 tbi i have one. Did you hook the IAT back up when you installed the open element? it has a vacuum line running to it. That could possibly be part of your vacuum problem. The Map sensor is mounted to the right of the a/c box on the lip of the cowl has a single vacuum line running to it. You said it was unplugged. my car ran like crap when mine went bad, after it was replaced it was fine. Trace all of your vacuum lines if al else fails, somewhere i believe in the tech articles theres a vacuum diagram (maybe, maybe not) I found one somewhere spend the $15 and replace all your vacuum lines since they're old and probably dry rotted. That's just my opinion on things though

 

Yes I know the 305 and 350 both have 3.48" strokes, and the 307 has 3.25" so not only can it take more RPM, but the 307 has a larger piston, so it can breath better. Which further increases High rpm capabilitys, and also helps at low rpm. Kinda the difference between a 302 (chevy) and a 305, just right between the two.

I left IAT hooked up, but not installed on the aircleaner, I have it wired up by the MAP sensor. The little vacuum line I capped off. I belive I have an extra map sensor I can try hooking that one up.

Once I change/work on something, should I unhook the battery so the computer can reset?

 

I would disconnect the battery. It will clear the codes and you'll know that the codes are valid and not old.

 

unplugged it and let it sit a few minutes, drove it for a little while and rescanned. I'm only getting code 24. Fault in the vehicle speed circut. Could This be causing it to do it? The car has a TH 350 andnothing is hooked to the tranny.

Going on an idea here. Will the computer run different timing when the car is in gear and going down the road? If so maybe the tranny is whats causing it.

How would I go about putting an old non computer controlled HEI in the car? I'm thinking about trying this tonight. Like I said in a revious post the timing feels like it isn't advancing enough. If I could drop in hei and the injectors will still work properly, than This is worth a try.

 

try using a chip from a manual car. it is possible that something is happening with the TCC lockup stuff, that is about all i can think of.

 

from what i've heard it doesnt matter what the stroke is it's the parts thats its put together with. thats why if you ask anyone about the chevy 302 they'll say you could rev em to the moon. but thats just cause they were built with the right parts. Any motor can rev that high with the right parts.

you said the speedometer wasnt hooked up to the tranny? thats whats throwing the vss code. if it doesnt read anything it'll throw a code. My speedometer cable locked up and broke. It was throwing a code 24. it has something to to with the ecm going through the fuel tables but not recieving any response from the vss.

 

about the stroke that's somewhat true, But a bigger piston does let it breath better. About the strocke it makes for better rpm for two reasons. When you shorten the stroke your bringing the weight closer in, so it's not stressing parts quite so much. The bigger reason is that the shorter crank slows the pistons dowm, thus at higher rpm there is a much better negative intake pressure signal to the manifold...in other words a longer stroke makes the piston go that much faster and it's going so fast (at higher rpm) it can't get a good draw. Rule of thumb is you gain roughly 500 rpm for every 1/4" less of crank throw. You're right about the parts you put it together with though, Your cam will need a lot of duration with stiff valve springs and your intake and heads are all going to have to flow really well.

So could the vss be throwing te ecm bad enough to do what the car is doing? Running good now at very light throttle and good at full throttle if you're over 2500 RPM

I'm just going to start a new post aobut the hei question.