For those who know my story, update and need help
08-08-2012, 07:45 PM
#1
3rd Gear Member
Thread Starter
Join Date: Feb 2012
Location: Canada, Montreal
Posts: 648
For those who know my story, update and need help
alright guys, at first, id like to please ask you not to tell me things I already know about the fact that buying a heavy modded car is a bad idea, and all that stuff, im really going nuts with this, id like to just lets you know whats up right now and need some opinions.
short story from last two week:
after bringing my cammed mustang to the tuner cause it ran so damn bad, made 330 rwhp, tuner putted a roush tune on it and made close to 400 but the car was running horrible on idle with the cams, he suggested putting back stock cams for better and easier appreciation of the car, which i said fine go for it, result: car back firing big time when engine is cold. Tuner ran some compression test and noticed weak compression saying this car already had a problem. I then rolled with the car for a 3-4 weeks until for no reason in the same week I broke TWO radiators, 1-2 inch crack in it, coolant all over, why? No idea, bad compression? back firing on idle giving too much pression on the radiator? maybe.
Then finally my uncle who own a mustang shop stripped the engine to remove the heads, we tested them, two heated valve, 2 cylinder compression were at 6 while the rest at 20. one of the head had a 4 milimiter imperfection, engine heated, prolly was like that when I bought this car, rebuilded the head correctly (which are ported head, not original it seem) we then tied together everything still with the stock cams to play it safe, start the car, pow pow pow back fire STILL. Yesterday we gave it a last try putting back my cams (prolly hot rod if you judge by the sound clip im giving you) and guess what, no more back fire! just the usual one when accelerating and remove foot from throttle, can hear a few back fire some time, but I got long tubes no cats, guessing that doesnt help.
Now, I was all happy getting my car today, back with the cams sound and stuff, no more weak compression in cylinder but still wondering why the f*** did the stock cams make back fire like that.. I start the car, clean cams idle, I decide to load the tune made by the tuner that gave more hp, horrible idle, car almost died, took time having the rpms stop bouncing in rpm, definitly not made for aftermarket cams ! eff it, reload main tune, leave the business, it pretty hot out there like 33 degree, try accelerating, NO POWER, the car just die in rpm, like if the timing was horrible, or some kind of misfire...discouraged i drive like a pappy home, the car was doing exactly the same thing when I went to bring it to the dyno, it was getting worst to worst day by day, but now what I just drove was totally top of it, no power at all, no reaction, full throttle would sloooooooooooowly pull me out of the 2-3k rpms .
(almost done guys thanks for reading all)
I then parked the car, waited until 30 minutes ago, cooler outside, went for a ride, the car reacted normally, power is ''oK''..feel like the 330 rwhp iit putted to the dyno, no misfire etc, really need to re-tune it yah ok..but why in hell did it do so when it was hotter? Could this be a timing issue in the tune? what your opinions on the cams affect of the back fire, could my heads not fit the oem 4.6 cams ? does that mean re-tuning the car correctly would cost me a billions dollars cause they seems pretty tricky to tune. you should see how horrible were they running with the new tune. no way to get ANY power either.
What you guys thinK? Should I go waste my money on the dyno or should I check for more engine problem..I'll have to recheck the compression, really though this woulda changed a bit of the car'S reaction.
here the cams video, sound mean, but my engine sound really weird.. a little metalic noise, and a really lound blower idle, dont like that.
I seriously need any opinions, I dont wanna call everyone around for more informations, id like to give everyone that helped me on the car have a break right now so I can make sure which path to go and be sure it the good way to head right now.
THanks alots guy, hopefully you do understand how tired this is getting. 1300 kms drove this summer with the car, including 3 road trip to the 2 hours dyno(500 kms)
short story from last two week:
after bringing my cammed mustang to the tuner cause it ran so damn bad, made 330 rwhp, tuner putted a roush tune on it and made close to 400 but the car was running horrible on idle with the cams, he suggested putting back stock cams for better and easier appreciation of the car, which i said fine go for it, result: car back firing big time when engine is cold. Tuner ran some compression test and noticed weak compression saying this car already had a problem. I then rolled with the car for a 3-4 weeks until for no reason in the same week I broke TWO radiators, 1-2 inch crack in it, coolant all over, why? No idea, bad compression? back firing on idle giving too much pression on the radiator? maybe.
Then finally my uncle who own a mustang shop stripped the engine to remove the heads, we tested them, two heated valve, 2 cylinder compression were at 6 while the rest at 20. one of the head had a 4 milimiter imperfection, engine heated, prolly was like that when I bought this car, rebuilded the head correctly (which are ported head, not original it seem) we then tied together everything still with the stock cams to play it safe, start the car, pow pow pow back fire STILL. Yesterday we gave it a last try putting back my cams (prolly hot rod if you judge by the sound clip im giving you) and guess what, no more back fire! just the usual one when accelerating and remove foot from throttle, can hear a few back fire some time, but I got long tubes no cats, guessing that doesnt help.
Now, I was all happy getting my car today, back with the cams sound and stuff, no more weak compression in cylinder but still wondering why the f*** did the stock cams make back fire like that.. I start the car, clean cams idle, I decide to load the tune made by the tuner that gave more hp, horrible idle, car almost died, took time having the rpms stop bouncing in rpm, definitly not made for aftermarket cams ! eff it, reload main tune, leave the business, it pretty hot out there like 33 degree, try accelerating, NO POWER, the car just die in rpm, like if the timing was horrible, or some kind of misfire...discouraged i drive like a pappy home, the car was doing exactly the same thing when I went to bring it to the dyno, it was getting worst to worst day by day, but now what I just drove was totally top of it, no power at all, no reaction, full throttle would sloooooooooooowly pull me out of the 2-3k rpms .
(almost done guys thanks for reading all)
I then parked the car, waited until 30 minutes ago, cooler outside, went for a ride, the car reacted normally, power is ''oK''..feel like the 330 rwhp iit putted to the dyno, no misfire etc, really need to re-tune it yah ok..but why in hell did it do so when it was hotter? Could this be a timing issue in the tune? what your opinions on the cams affect of the back fire, could my heads not fit the oem 4.6 cams ? does that mean re-tuning the car correctly would cost me a billions dollars cause they seems pretty tricky to tune. you should see how horrible were they running with the new tune. no way to get ANY power either.
What you guys thinK? Should I go waste my money on the dyno or should I check for more engine problem..I'll have to recheck the compression, really though this woulda changed a bit of the car'S reaction.
here the cams video, sound mean, but my engine sound really weird.. a little metalic noise, and a really lound blower idle, dont like that.
I seriously need any opinions, I dont wanna call everyone around for more informations, id like to give everyone that helped me on the car have a break right now so I can make sure which path to go and be sure it the good way to head right now.
THanks alots guy, hopefully you do understand how tired this is getting. 1300 kms drove this summer with the car, including 3 road trip to the 2 hours dyno(500 kms)
Last edited by mighted1987; 08-08-2012 at 07:50 PM.
08-08-2012, 11:19 PM
#3
2nd Gear Member
Join Date: Jul 2011
Location: Colorado
Posts: 289
The compression test does not make any sense combined with the rest. Compression is either bad or not. There's generally no "sometimes" bad. It will not run good at all with two bad cylinders. BTW, 20% cylinders will not run properly. The only way it could be sometimes bad is with a sticky valve. Maybe a valve spring or two are broken.
My first, choice, however, is that there is a problem in timing. I'm not familiar how to time the cams in the 4.6, but the backfiring tells me that timing is way off. It could be cam timing or ignition timing, but one or both are out of whack.
Bad cam timing could explain the compression loss. Valves are opening at the wrong time letting compression escape. At that point, the cylinders are not bad. Get it in proper time and the compression will come back.
Also, be careful. Bad cam timing could force a valve into a piston and bend or break both. Then you will have a bad cylinder.
My first, choice, however, is that there is a problem in timing. I'm not familiar how to time the cams in the 4.6, but the backfiring tells me that timing is way off. It could be cam timing or ignition timing, but one or both are out of whack.
Bad cam timing could explain the compression loss. Valves are opening at the wrong time letting compression escape. At that point, the cylinders are not bad. Get it in proper time and the compression will come back.
Also, be careful. Bad cam timing could force a valve into a piston and bend or break both. Then you will have a bad cylinder.
08-09-2012, 12:00 AM
#5
4th Gear Member
Join Date: Aug 2006
Location: Los Angeles, California
Posts: 1,277
Keep it off the dyno, for one. Second, buy a factory service manual, and read up on the symptoms you are having. Are you getting a CEL? Is the thing throwing codes (sounds like it should be). Do you have a code reader?
Sounds like it may be a heat related problem, if you cracked two radiators. What was the temp gauge saying?
All in all, our cars have a LOT of sensors. It's possible one or more are bad, which would probably cause some of the symptoms you are describing. For example, your timing may be getting way to retarded or advanced (which would explain the overheating), but it may be because the PCM is getting bad info from a bad sensor, or perhaps the cams were not indexed correctly.
Sounds like it may be a heat related problem, if you cracked two radiators. What was the temp gauge saying?
All in all, our cars have a LOT of sensors. It's possible one or more are bad, which would probably cause some of the symptoms you are describing. For example, your timing may be getting way to retarded or advanced (which would explain the overheating), but it may be because the PCM is getting bad info from a bad sensor, or perhaps the cams were not indexed correctly.
08-09-2012, 04:29 AM
#6
3rd Gear Member
Thread Starter
Join Date: Feb 2012
Location: Canada, Montreal
Posts: 648
The weird part is the car ran really Good with the new tune and stock cams, but it was back firing Mad on idle when engine was cold also, and for The compression it was bad cause of the damaged heads, two heated Valve not sealing properly. But the compression is suppose to be good now we repaired the heads, and swapped
Back the hot rods cams in and no more back fire when engine is cold but ****ty power and worst on hot temp, ive never gotten any check engine or engine heat meanwhile, and if my new cams are the problem, im screwed cause the stock cams make horrible back fire in the exaust and that seems to damage my
Radiator
Back the hot rods cams in and no more back fire when engine is cold but ****ty power and worst on hot temp, ive never gotten any check engine or engine heat meanwhile, and if my new cams are the problem, im screwed cause the stock cams make horrible back fire in the exaust and that seems to damage my
Radiator
Last edited by mighted1987; 08-09-2012 at 04:31 AM.
08-09-2012, 09:16 AM
#7
4th Gear Member
Join Date: Aug 2008
Location: Panama City, FL
Posts: 1,214
I think you need to take the engine back to completely stock and make it run correct, even if it means pulling and rebuilding. Then throw out any past tunes and cams you have used and get a new tune from a known tuner. This is the only way to make it all correct.
Not sure you mechanic knows what is happening under the hood of that car......
Not sure you mechanic knows what is happening under the hood of that car......
08-09-2012, 09:39 AM
#8
3rd Gear Member
Thread Starter
Join Date: Feb 2012
Location: Canada, Montreal
Posts: 648
Last attempt tommorow, redoing
Compression and leak down test tonight, if all ok leaving the
Car to a new tuner, if bad compression again stock engine goin in 100% guaranteed, same story if the tuner see by himself that there no good tune able to make this engine work properly, ill throw stock engine in. This engine is all forged with after market BIG ported head etc, with a 80mm master flow throttlr body? Could Also be the mix of too much moding making a bad Combo and losing easily a 100whp somewhere.
Compression and leak down test tonight, if all ok leaving the
Car to a new tuner, if bad compression again stock engine goin in 100% guaranteed, same story if the tuner see by himself that there no good tune able to make this engine work properly, ill throw stock engine in. This engine is all forged with after market BIG ported head etc, with a 80mm master flow throttlr body? Could Also be the mix of too much moding making a bad Combo and losing easily a 100whp somewhere.
Last edited by mighted1987; 08-09-2012 at 09:41 AM.
