Big problem need help

[ExplodingGopher]

Ok, i just put in a b303 cam in my engine today and when i got it back together and started it for the first time and adjusted the timing to about 14-15* BTDC and I broke it in at 2000 rpm for 10 min. as it said on the box. after the break in i adjusted the idle to about 900 rpm and after that i played with the idle adjustment screw and it does nothing and really runs even worse now. Does the computer have to learn the new idle ro something? it idles like crap, like a drag car and occasionally backfires. It revs great but idles like crap. Also no power brakes and running very very rich. The car has brand new stock lower intake and new stock ported heads. Im thinking its a vaccuum leak somewhere but cant find it. I have to wait till tomarrow to get a vaccuum gauge so im wondering what you guys think. The previous owner claims to have a performance computer chip in it, im thinkin if it didn't, with that kind of idle it would throw up a code and the idiot light would come on, but i have no warning lights on, little if no vaccuum to power the brakes, crappy idle, and running way too rich. Could all this be just from a vaccuum leak or could it also be the computer. I have a pro flow 75mm MAF and 19# injectors. Could adding a vaccuum canister get my brakes back ?


Just for giggles, when it was running ok, that cam is killer man, tap the gas and it instantly responds with some balls. Awesome cam.

 

[HISSIN50]

im not sure, but i bet others will want to know the info on your car (year, etc) and mods. did you install it straight up? stuff like that.

 

[ExplodingGopher]

I helped install the B303, and it was done correctly.

black '91 LX hatch

Mods are 75mm MAF, no A/C, smog pump not hooked up, computer chip (according to previous owner), Shift kit AOD, new stock lower, new stock heads ported and cleaned, new stock rockers lifters and pushrods, timing chain is dead on, timing adjusted to about 14-15* BTDC, 3.73 gears, dynomax headers, O/R H pipe, flowmaster no chambers dumped (loud as hell), new water pump, 19# injectors. im just not sure if its a vac leak right now but just wanted to know what you guys thought.

 

[ratrapp]

i have a b-303 in my car and was bone stock,i hadn't did anything except convert it to mass air at the time and it idled rough but cosistent and never backfired or popped back through the plenum.also i never had a problem with vacuum for my brakes.it sounds like you don't have enough timing in it(balancer possibly spun or a notch out of time)or you have a bad air meter.

 

[ECU5.0]

take the chip out or drop your timing back...youre running too much timing. thats all i have to add

 

[ratrapp]

if he's is actually running 14or 15 degrees how can that be too much?i run 16 to 18 degrees on my b -303 and we ran 22 degrees on my buddys 95 with an e 303.it had no power and popped through the plenum with 16 degrees.we had a lot of trial and error before it was right.and yes it had a brand new ford balancer and we used my mac timing light so i'm sure our numbers are correct.

 

[ECU5.0]

a chip advances the timing already...and than adding more timing to that. i just thought it might be a good suggestion. also, just because you and your buddy can run that much timing doesnt mean everyone can. there are people that cant run more than 10 without pinging. just depends on the engine

 

[ratrapp]

wasn't arguing,i'm not familiar with all types of drop in chips but a few years ago a friend of mine got an ads superchip for his 93 gt and the way it advanced the timing was what they called an octane bar that goes in front of the dist. that gives it more total timing so i'm not sure what kind of chip he has or even if ads still does there chips like this(5 years ago)so removing the chip probably wouldn't help his situation but i believe either way it sounds timing related whether high or low.he needs to double check his work and experiment with the timing.

 

[bock]

Your power brake need vaccum to work, ist the bigest vacc hose you have. if ist not plug,you have a big vacc leak and it causing your bad hidle.Chek this.

 

[ExplodingGopher]

Problem possibly solved

OK today we figured out it was the lower intake rear and front seal. we sprayed some silicone spray near the back lower seal and the engine straightened up and idled great for a few seconds then went back to crap, we sprayed water in the same spot to check for the leak and the engine bogged down. same thing with the front. I used a mr. gasket set for the gaskets and the front and rear gaskets must've slipped somehow when we put te lower intake back on. Im buyin a set of Felpro gaskets for it tomarrow. But yeah bigtime vaccuum leak from there and hopefully better gaskets and careful reassembly will fix the problem, cause felpros have a ridge on them to make them not slip. but i'll let you guys know for sure soon.

 

[HISSIN50]

i could be very wrong, but i think a lot of guys use a good amount of RTV in lieu of, or in addition to the gaskets on the ends.....check/confirm with someone else before doing so.

 

[timewarped1972]

the vacuum leak i believe would have to be on the head to manifold surface itself, not just the end seals.........if it we're only an end seal it would leak oil but i don't believe would cause a vacuum leak...........end seal being the block itself to bottom edge of the manifold.....to help prevent the head to manifold gaskets from slipping, use some gasket adhesive( high tack gasket adhesive, and buy some carb cleaner incase you need to clean excess off of anything ) on the gasket to head surface, set the lower intake on that with no sealer just so it allows the gasket to dry/stick in place to the head. dont bolt it down just set it on so the gaskets will stick to the heads. then after their stuck in place, take the lower manifold off, i use a skim ( very thin! ) coat of rtv around just the water outlets. you can use either rtv or the supplied cork gaskets for the end seals, the rtv works great but can be tricky unless you've don it a few times and or are good at getting the manifold straight down on it without moving it around ( especially the rear one ) ,and if you use the cork gaskets use a dab of rtv in the corners where they meet the heads. don't forget when you use rtv it does need to dry. also, if you sprayed water at the end seals ( the flat one's that are on the block not the heads) and it bogged sounds like your end seals and your head to manifold gaskets slipped, unless when you say end seal you mean at the end of the head/manifold area. either way i'd change your oil as well incase you got any water in the engine.

 

[ratrapp]

timewarped is right all that would cause is a big oil leak.the only way there would vacuum there is if the intake gaskets themselves would be leaking.do use some good black rtv,not that crappy blue that never hardens up(it's not going to)

 

[ExplodingGopher]

Problems solved thanks for the help

It turned out that the front and rear gaskets for the lower intake slipped when we lowered the intake back down and tightened it up. We used better felpro gaskets and a crap load of black gasket silicon and the problem is gone. Brakes are back, car running awesome as ever. Great cam by the way. One other problem arose after finishing installation, the car ran alot hotter than normal around 250*. I went and bought a 160* thermostat for it today and the stock temp gause reads around one and a half lines all the time, sometimes up to two lines occasionally, but the car runs awesome now. Maiden voyage was tonight and man that cam starts pullin and doesn't stop. Thanks for all your help everyone.

 

[HISSIN50]

glad you got it fixed! next mod should be a real temp gauge.

 

[Michael Yount]

Or you can keep the stock gauge, and the next mod will be an entire overhaul from overheating it.

 

[ironmedic]

i used that blue gasket stuff on my lower manifold gaskets. i double coated it on both sides and made a perfect seal

 

[KJNY]

yeah, i had that same problem... couldnt find a vacuum leak and it turns out there was no RTV sealing anything between the head and lower manifold (serves me right for asking a friend to do a few things on my car while i was working one day). anyways i got all those problems. terrible idle, richness, etc. i solved the problem by laying a pretty thick coat of RTV on both sides of the gasket. runs like a whole new car now