Ford Racing Engine with E303 Cam behaving badly

[BobbyGlatz]

I am not much of an engine guy but I recently had BC Bronco's put a ford racing 302 EFI with headers and AOD transmissions and all the good stuff. Problem is since I got it back it idles poorly, dies when put into gear. (despite 2500 torque converter) One day it idles fine and others it is intolerable. Also, the power for the engine is at the high RPM's and I would greatly prefer torque over high rev power. Overall it has been an unpleasant experience.

I have been told that it is a vacuum problem related to the cam. Problem is I don't know about replacing the cam for fear that it will mess things up worse.

(I have already worked with chuck at BC Bronco's and he is out of ideas. Initially he tried to smooth things out but couldn't and now sort of feels that he has done his best and it is my problem.) Anyone have any suggestions.

Someone suggested taking to a dyno tune place but I am in deep south texas (McAllen) and the nearest place that I know about is in houston. Plus I am trying to keep costs down.

 

[01Dudley]

What is your idle set at when you are just sitting there in park? Have you tried putting some more timing in it? Does the idle fluctuate? Do you have a EGR valve? Has the computer been adjusted to match your set up? What heads are you running? Have you checked the rocker arm adjustment? This motor will always make high end power and not torque. That is how it's built.

That is not a overly huge cam and plenty of Mustang guys run that cam no vaccum issues, so I wouldn't think that is your problem.

 

[ransil]

Dyno tune, I installed about the same combo and a dyno tune straightened it out

edit:

just checked the cam specs the one i worked on was an x303 cam, the e303 is a milder cam, i agree with everyone else here, something is wrong gotta fix that before a dyno tune.

start checking things as mentioned:
vacuum leak
MAF sensor
harness connections
fuel pressure

I don't use K&n filters on MAF setups I use a dry filter ( AEM )



Sent from my Galaxy Nexus using Tapatalk 2

 

[Phil76]

These guys have a dyno right there in McAllen
DeLeon Auto Accessories
2621 South 23rd Street
McAllen 78503
Phone : 956-682-1801
Email : jdeleon@deleonauto.com
Website: www.deleonauto.com

 

[BUCKNBRONK]

he put a new motor and tranny in and it runs like shit and its your problem? thats not too cool from BC to do that to u. do u have the specs for the motor? - e303 is not really a hot cam, its mid range. u should not be having issues with it at idle. ur issue has nothing to do with the cam, unless its flat from improper break in.

that motor and cam should be about right, i dont know why they are telling u its a top end build- the e303 is basicly stock. it should be a good set up.

 

[bmc69]

One day it idles fine and others it is intolerable. .

That does not sound like problem directly attributable to the "tune" to me. That sounds like there is actually a glitch somewhere in cabling, sensor(s) or the like.

 

[BobbyGlatz]

Wow, Thanks everyone. This was my first time posting and within 1 hour I already have something to work with. I have been trying to find a dyno place around me but was unable to find one. I am not sure how you did it but thank you very much. I already called the dyno tune guy and he referred me to someone who can check for a vacuum leak and if there is no leak can proceed to doing a tune with a chip. I have asked my mechanic to sign on under my name to answer some of the technical questions that you have raised. Hopefully he will do it today sometime.

Thanks very much for the help you have given me so far! Heart warming. This damn thing has been frustrating me and my mechanic for a year and a half now. (helping put my mechanic's kids through college.) Bronco peeps are good Peeps!

 

[rastiss]

i assume mass air flow system? i have chased a deal similar to this, first one was a probe, the second a v-10 motorhome. they had both been thru numerous shops and techs and nobody could find anything. fuel pressure, vac leaks, diagnostic showed nothing. i ended up finding that the mass airflow sensor had foreign substance on the little wires. the probe was some kind of fuzz, the rv was a june bug hung up on it from the guy replacing his air filter. not saying that's what it is but it is easy to check. such a simple thing created hell!

 

[Timmy390]

i assume mass air flow system? i have chased a deal similar to this, first one was a probe, the second a v-10 motorhome. they had both been thru numerous shops and techs and nobody could find anything. fuel pressure, vac leaks, diagnostic showed nothing. i ended up finding that the mass airflow sensor had foreign substance on the little wires. the probe was some kind of fuzz, the rv was a june bug hung up on it from the guy replacing his air filter. not saying that's what it is but it is easy to check. such a simple thing created hell!

Over oiling a K&N style filter can cause you all kinds of MAF problems too....Been there done that......

They make a cleaner for it or maybe I used some electronics cleaner...

Tim

 

[AZ73]

I investigated that engine when I was shopping for one. I spent a considerable amount of time on the phone with Ford Racing talking about what I was going to be putting the motor in and they told me a lot of guys that put that motor in a Bronco swap the cam out for the exact torque band reason you stated. They gave me the name of a company that I could get more fitting cam from and said they would uphold the warranty if I used their cam. That's an issue for your torque band, but not for the way it's running, and the way it's running has nothing to do with the 303 cam. As others have said it's probably a sensor or some other electrical issue and you'll save time and money going to a tuning shop to narrow it down. Only other thing I can think of is a sticky advance on your distributor. Is it electronic? or maybe a plug wire burned through to your header and it's grounding occasionally?

 

[rustbucket]

he put a new motor and tranny in and it runs like shit and its your problem? thats not too cool from BC to do that to u. do u have the specs for the motor? - e303 is not really a hot cam, its mid range. u should not be having issues with it at idle. ur issue has nothing to do with the cam, unless its flat from improper break in.

that motor and cam should be about right, i dont know why they are telling u its a top end build- the e303 is basicly stock. it should be a good set up.

I think you're jumping to a lot of conclusions here. I, personally, from the OP's post can't tell where the engine came from. Who supplied it? In what condition was it in? He didn't say it was new. It may have been, but the problem could have been created by the engine builder, not BCB. Without knowing more information, I think this was a bit unwarranted, or at the very least premature.

That being said, I agree with you that the E303 really shouldn't be a problem.

Bobby, what ECU are you using? What injectors? MAF? Where all sensors new?

Have you pulled codes? If so, what are they?

Have you tested the IAC valve? Checked for vacuum leaks?

Make sure you have good ground to the ECU.

 

[ransil]

for vacuum leaks find or get or make a smoke machine , sometimes you can spray shit all day long and not find them.

 

[75junebug]

To add to what rust bucket said above...Check the relays, especially the one under the dash near the computer. I had EFI running great for 18+ months out in SC, but when I moved back to South Texas in Nov 09, I developed problems at Roundup. I tested everything, replaced dang near everything(except the relays under the dash). It was only after I went back to my trusty Qjet/HEI dizzy combo, and was removing the EFI Harness did I find the evidence of moisture damage on the ECU relay. I didnt look because I assumed being under the dash was out of the weather. McAllen aint much different than Corpus.

 

[73azbronco]

The maf sensor fouling while a good idea for every problem other than idle issues, is probably not an idle fault causer, the idle circuit controls the idle, not the maf. Get yourself an Efi trouble shooting checklist.

http://www.thedieselstop.com/faq/9497faq/maint/stj/stj30006.htm

 

[rastiss]

The maf sensor fouling while a good idea for every problem other than idle issues, is probably not an idle fault causer, the idle circuit controls the idle, not the maf. Get yourself an Efi trouble shooting checklist.

http://www.thedieselstop.com/faq/9497faq/maint/stj/stj30006.htm

say what you want BUT it CAN absolutely affect idle. both of the these vehicles i mentioned ran absolutely fine EXCEPT at idle. no codes, no vac leaks, fine fuel pressure, etc...i heard all this before from the so-called super techs that had already worked on it. BUT i was the one that fixed them both! i'm just a body and paint guy so what would i know...;D

 

[anoblefox]

I have to disagree with the statement that it should be OK for a bronco. I had the same cam in my t-bird with 2.02 valves and aluminum heads. It MAY be milder with smaller cylinder heads but I had to go BACK to the stock cam in TWO of my customers cars in early (much lighter) Mustangs at their expense. This only I strongly suggested using the stock cam from the beginning. I will say this, both the B 303 and E 303 LIKE a lot of initial timing and this really helps the idle. My 3700# T bird was set at 18 degrees initial instead of ten and ran well. This should not be a problem with aluminum heads, just rember to change it back before a smog check.

 

[firehawk]

I had similar issues with a stock 302. Sometimes it would drive fine and others it would stall.

Turned out if had a vacuum leak, one of the ears on the upper intake that hold it to the lower was broke. I tig welded it back on and that helped. Also the Idle bypass solenoid can be suspect of a stalling issue. I also had other hard start problems and the battery was ok but after installing a new one the problems seemed to clear up even better.

So check all electrical connections, at the battery and grounds. Battery voltage.

Have you checked fuel pressure?

I also swapped out the wiring harness the PO installed with a ford racing harness and chased problem after problem, not sure what cured it but it runs and drives great now.

What harness are you running?

 

[EricLar80]

Been there, done that with the E303 cam. Go to this cam, or something similar, and you will not be disappointed in low end torque or mid range power. Not to mention that it idles like a dream with a stock EFI setup.

Eric

 

[Bronco73]

I have seen this problem before but it was on a 94 mustang, not the common the 87 to 93 efi system.

 

[bmc69]

FWIW..I have two E303s sitting on the shelf that I removed and replaced to make the 5.0s behave better for EB and trail use. But I didn't want to cloud the issue here because this "sometimes idless great and other times, terrible" thing has nothing to do with why I didn't like the E303 cams...IMHO.