So me and Drinkmorebeer were working on his 89 350 TPI tonight, we set the timing to 2 or 4 degrees advance, this cleared up a really rough Idle, He is still getting backfires and major bog issues when in drive. He steps on the gas and it just wants to die, but redeems itself and starts to go. He is missing about 50% power, his engine idles at 1500 in N but drops to about 700-900 when in drive.

I was thinking that the previous owner got the dist 180 backwards. Before messing with the timing, it would backfire through the TPI, after the timing its just out the exhaust.

He replaced his fuel filter, wires, dist ect, any thoughts would help !! Trying to get him running perfect before he heads to the folsom meet !! Thanks in advance !!


*on a side note, anyone who does a hackjob on wiring up the fan should be shot!! will post pictures when i can take them of this hack job!, or drinkmorebeer can post some!! For real, this fan job, is below ******* jimmy rigged standards LOL*

 

Check codes. I would start there. If no codes then firing order, spark at each cylinder, vacuum, compression, and fuel pressure.

Not sure what the timing should be on that specific engine. Did you set it with the trigger wire disconnected and set it to the number posted on the hood?

 

Yep, disconnected the EST, set it to 2-4 degrees cant remember which one.
It ran so much better, but still feels like the timing is wrong.

No codes except for the EST that i pulled.

 

/bump any other thoughts ?

 

Check the distributor to see if it is off a tooth.
See if the rotor lines up with #1 post with the crank positioned at the correct TDC mark ( 0* degrees )

 

[quote=rough;3996943]

his engine idles at 1500 in N but drops to about 700-900 when in drive.



That sounds like a vacuum leak... when you give the engine a rev it should drop to idle as fast as it reved.

If it floats at high rev and slowly drops there would definatly be a vacuum leak.

When you do the timing make sure the engine is up to temp. with engine running use a jump wire and jump terminal B to A on the diagostic plug under dash. This should keep the timing from advancing.

if it doesnt all you can hope for is that the EST bypass works the same when you unplug it. It wont always work either.

Set your timing at 6 degrees BTDC. Idle should be at 700rpm. Its the same for auto and manual trannys.

be sure to recheck the timing after you tighten the distributor. if it looks good, with the engine still running take your jump wire off or plug your EST back in. if this hasnt fixed your problem its not a timing issue.

If you have a way to check fuel pressure ... it should be 41-47psi.

 

The injectors just need to be changed. Im almost sure of it. Either change them out or clean them. Im pretty sure that Pep Boys does injector cleaning, I have a friend who works at Pep Boys and he does them by using a 95 to 99% alcohol solution. My car was doing the same thing and i changed the injectors and all is fine. There is a BIG difference now.

 

Distributor a tooth off is silliness - if you were able to set the timing, which tooth the distributor on is moot.

I don't know particulars about TPI, but I was under the impression the base timing was more like 6 degrees. Wouldn't cause those symptoms, though.

Check fuel pressure. The symptoms sound like lean running, which could be injectors, but could be fuel pressure, too.

 

He did replace the fuel filter and said he emptied it out and a bunch of muck came out. Will seafoam clean the injectors out? Wish it was TBI then i could tell if the injectors were fuq'd lol

Can you check the Fuel pressure on the rail from the passenger side "rear" valve?


BTW thanks for the responses ! Trying to figure it out before he goes on the folsom run !

 

see i was thinking vacuum leak myself, but since it varies so much i am unsure. I would think that if it was a vacuum leak it would always be high rpms. I ran seafoam through through the fuel already. It seems to be that when i slow down fast or want to take off fast it throws a fit.

I noticed a difference with the timing. But im still backfiring like crazy. It seems to get real shaky once it gets really warmed up as well. What makes me think its a fuel issue is the amount of cranks it takes to finally kick over.

 

I don't think a vacuum leak would cause that much of a problem. He is missing about 50% power also.
Whats the easiest way to check for a vacuum leak?

 

My thoughts are vacuum leak but you need to correct your timing to 6 degrees.

your car in neutral should idle at 700rpm or very very close to it. if its up there in the 1200rpm+ then you have a big leak.

Try taking a can of carb cleaner and spray around everything that has a gasket above the heads with the engine running. listen carefully to the engine rpm and if you find a spot where the rpms change noticeably ... it will be your leak.

you wont set your car on fire by doing that. doesnt mean directly spray the exhaust either. lol careful not to get it on your cars paint.

 

Thanks !! When i pulled a vacuum line that was in the way of the DIZZY hold down bolt the engine surged, but will try the carb cleaner,
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WE will readjust the timing to 6 degrees also, is the engine suppose to race up when adjusting the timing ? if you turn it a few degrees one way the engine races, the other way it bogs hardcore and smoke come out the exhaust hardcore.

 

I have had the intake gaskets blow out on one of my cars twice. it caused it to idle high and when put in gear it would die.... so i turned idle up to 1200rpm and when it was in gear it would drop to 600rpm and idle rough.

look into that

 

With that gasket blown, it should suck the carb cleaner in where its blown out the gasket?

 

if you advance the engine too much it trys to roll the engine backwards...reason for rough

if you retard it to much you a firing after top dead center and your not burning fuel completely causing it to smoke.

set it at 6 degrees how i posted earlier. regardless of how it idles. if you not idling at 700rpm you have other problems.

trouble shoot at something else

 

yes it should... your listening to how the engine reacts.

if it only sucks alittle carb cleaner the idle will raise... if it sux alot the engine will stumble.

you wont visually see anything. just listen to engine rpms.

if its on the bottom side towards the lifters you would never know. dont get happy any just pull the top end off. go over everything twice and be sure it nothing else before you do that.

 

Thanks much for your input! Drinkmorebeer will be rolling by on sat, he gets off to late on FRI and we will give it another go ! Ill post back with the results !!

 

got them apple bottom jeans and the boots with the fur

 

Disconnect the air-cleaner end of your MAF so you can cover the hole with your hand. Make sure the power brake vacuum port and the PCV port on the intake are plugged. If you cover the air intake hole and the engine still runs then I'd look for a vacuum leak.

Some things that cause similar problems are leaks between the MAF and the TB, and if you have a bad fuel pressure regulator the vacuum could be sucking fuel into the intake, though that wouldn't kill half of your power.

 

THanks much !! well try that to !

 

ill pick up some carb cleaner omw up.

 

figure anything out yet