engine seems to flat line after 4000rpm

Topic: engine seems to flat line after 4000rpm (Read 1915 times) previous topic - next topic

engine seems to flat line after 4000rpm

July 05, 2014, 11:29:38 PM

I have a 88 Etc that I've had over a year now and it has just recently started stumbling when u first start it I've lost fuel mileage and power. I noticed a high pitch noise once engine turned pass 4000 . Now when u turn past 4000 it just goes flat just need some ideas

engine seems to flat line after 4000rpm

Reply #1 – July 06, 2014, 01:29:51 AM

What does it boost to, and auto or stick?

engine seems to flat line after 4000rpm

Reply #2 – July 06, 2014, 05:16:52 AM

Car is 5spd and boost gage hasn't worked since I've bought car.
It was running good about two months ago now it seems to pull pretty good from 2500-4000 not as strong as it was but once I get passed 4000 it just dies out

engine seems to flat line after 4000rpm

Reply #3 – July 06, 2014, 04:11:04 PM

Run codes. all you need is a paper clip and a test light.

here's a vid of my running codes on my 87 5.0. Test should run abiut thttps://www.youtube.com/watch?v=9QSiS6wf7oU&feature=youtube_gdata_playerhe same.

engine seems to flat line after 4000rpm

Reply #4 – July 06, 2014, 04:11:35 PM

Oops, fat fingers, small phone.

https://www.youtube.com/watch?v=9QSiS6wf7oU&feature=youtube_gdata_player

engine seems to flat line after 4000rpm

Reply #5 – July 07, 2014, 09:32:09 PM

Thx didn't no u can read codes like that but i have a code reader just haven't done that figured it was something bigger considering the drastic change n way car run but it is a turbo car and don't no much about

engine seems to flat line after 4000rpm

Reply #6 – July 08, 2014, 12:11:09 AM

Code readers work exact same way, just uses a buzzer instead of a light.

the car will know something is wrong before you do, and it will keep a memory of the codes stored. so even if its intermittent, you should know.

most of the time with a turbo it has to do with a bad seal between the intake and turbo giving you false vam readings. this would easily show up in codes. should pin point your problem.

run codes and let us know what pops up, and we will go from there.

engine seems to flat line after 4000rpm

Reply #7 – July 08, 2014, 06:42:44 AM

TURBO COUPE engines eat the stock valve springs and cams . They normally will start floating @ or around 4000-4500 when they get weak. And flat cams are also common on the 2.3. I would have to actually drive the car to feel it but that is what it sounds like for your not pulling past 4000. If the car pulls hard up to 4000 and flattens out that is textbook valve float. The noise could be a boost leak that should be checked. And the stumbling is most likely something in the fuel system or ignition. You did not say weather you had a SES light on If you have no SES light i would check fuel pressure and a ripped coupling on the inter-cooler. Shooting a trouble like this on a key board is tough. But i will tell you i have changed many valve springs on the 2.3 in my career. But start with the basics. Just my guess without driving the car. have a good Tuesday guys

engine seems to flat line after 4000rpm

Reply #8 – July 13, 2014, 04:33:59 PM

OK I finally run codes on my TC .Here is my engine off test .
11-system ok 22 map or baro sensor out of range.
This is engine running test.
25-knock not sensed during dynamic response test.
34-there is 2-34codes n book and both r egr problems.
77-operator error.
74-boo switch fault.
Wat y'all think run car down hill lol

engine seems to flat line after 4000rpm

Reply #9 – July 17, 2014, 03:53:50 PM

Map or baro sensor out of range means you have some type of vacuum leak you need fixed. Intake leak = lost boost = less power/spool.

engine seems to flat line after 4000rpm

Reply #10 – July 17, 2014, 09:13:30 PM

NOPE Vain air turbo coupe no MAP. Baro so lets try this again. The BARO is not effected by vacuum leaks. Check the baro and either replace it or trouble shoot why the code is there. The TC uses BARO not MAP. Fix the code and when and if you still have the same issue we will go from there. To be honest in all the years i have been building TURBO COUPES i have never had to change a BARO sensor. Not that they can not go bad i never had a bad one. But that does not mean one could go bad. Did you check the cat to see if it is plugged up?? If the engine runs strong all the way up to 4000 and flattens out that is like i said valve springs. I would have to drive the car to tell that. I have changed dozens of bad springs on the 2.3 over the years. But that does not effect the bad start up trouble. You may have 2 troubles at that. Good luck and have a great friday guys.