dies when braking off throttle, or turning/braking off throttle.

[_onions_Belt]

only place i know to start is from when i got my 86' widebody. this will be my first post on the forum, as usually i can find a solution to my problems in the years of info in this forum but my problem i havnt found anything.

 

this is my 2nd 86 dodge conquest tsi. the first looked great but ran poorly and threw a rod. anyway i received my second one with 89,000 miles. paint was trash but ran pretty well and everything was there and then some. it has had a fuel cut issue since ive owned the car but i just keep it under 7lb 

about a week into ownership i blew up a jet valve and thought i blew a headgasket, i saw smoke i shut it down and tow it to my shop. crack the valve cover off to find a stuck jet valve and a broken rocker ear on the first rocker on the intake assembly. luckily by the grace of god it was one big chunk and i was able to remove the debree and it not damage anything from what i could tell. so next thing to do for me was put in a jet valve elimination kit to get rid of those and not have to 1 buy a new jet valve rocker and jet valve or 2 not have to convert my valvetrain to full mechanical valve lashers etc. at this time i took the lifters out let them sit in oil and took apart pretty much the whole head besides the valves and valve springs and the head itself. i also noticed the car run better without my mas plugged in, my first conquest did the same thing and i never ran it. ive done the same with this car and it hasnt ever given me issues. im fairly sure only very early production conquests and starions can do this.

This is when i realized that i had a brand new head, and heavy duty valve springs, and the upgraded "thicker headgasket", every bolt had a check paint mark, dropped the pan and same thing with the same paint and everything felt tight, leading me to believe this motor was rebuilt right before i got it. the head was squeeky clean.

i got the jve kit in and while i was away my dad put the sproket back on and stabbed the dizzy, when i got back was time to time the dizzy and tweak it. 

car ran ok after words but i never thought it ran just right and the car would over heat sitting in 1min or more traffic and was almost pointless to drive unless i was hwy cruising. so i have my buddy time the car while im gone at work and i drive it home and its on kill mode and running better then ever. i pull into my driveway about 20 mins down the road and its dusk and i noticed glowing coming from my engine bay, pop the hood, and my turbo header is glowing red/ orange hot. i found out the hard way and almost blew my car up that i need to do everything myself and by the book. so i time the car by the service manual with the vacuum adv unplugged at 10btdc. ever since car has ran pretty ok but still would over heat.

so i decide to redo the whole coolant system, new water pump,hoses, 160* thermostat, and a thicker aluminum cxracing radiator. still would over heat. untill i dumped a bottle of water wetter in the radiator and since hasnt broke the temp of the thermostat ive ran, i recommend that to anyone witha hot quest. i also did 2 12" slim fans on the back pulling and tied in the ac fan to push. absolutely fixed my overheating in oklahomas 105* days.

now ive got everything working good and staying cool i blow the stock turbo seals out so replace the cartridge with kinugawas stock replacement. it actually has done very well and havnt had issues boosting on it or having irregular temps it stays nice and cool with the motor. 

i received the car with a catless down pipe and i had the secondary cat deleted so now its straight piped to a muffler.

ive replaced 95%  of the vacuum lines as most were original but i will note the secondary box was deleted. but still had vacuum lines that tie back into the tb vac lines to the sensor. i deleted the egr valve, but it still has the top vac port routed with the thermo sensors etc, the bottom port is blocked off and the sensor is still plugged in, the secondary air control sensor is still plugged in and a vac line running into a junction with the thermo sensors and egr/ vac adv to the first port of the tb. second port is capped, third is for my bov, lower goes around engine bay for cruise etc already replaced, top one goes to my pressure sensor and guage. 

i should note the car already has new injector clips, ive dropped the tank and replaced the pump and filters, tank looked good. ive rebuilt my tb properly. replaced the alternator with the best i could get, my voltage guage reads just over the middle line on the guage but hasnt given me problems.  my cars struggled with oil pressure or at least what the guage tells me. at warm idle its at 1/4 on the guage, cruising it will be a tick over 1/2 on the guage. but i dont know if the guage is 100% accurate either. ive replaced all my fuse links. the ignition is brand new inside with a working hks turbo timer wired up,msd masterblaster2 coil, new plugs/wires,newer dizzy not brand new but not oem. has a 3 wire o2 but only 1 wire is connected and it looks poorly connected. it also had a safc under the gloved box with wires everwhere but not hooked up and working. just did the oil pan gasket and not sure where i could be losing oil pressure.

all of that info is to ensure alot of this car has been touched and 85% of my car has brand new parts on it to assess my wierd issue

 

about a month or two ago my quest decided to die with medium braking/ turning into a parking lot, clutch in no throttle. well over the course of a month it got worse. if im going 5-10 mph and lightly use the brakes or turn it wont die or if i keep my revs up to fight it stalling. its like just the right amount of braking at the right speed while off throttle it just kills itself immediately. medium hard braking it will instantly die, if you gentle on the brakes you can kind of regulate the stalling. so i think maybe a tps isc reset is in order. well at the same time my cars stopped over heating so i decide to put in a 180* thermostat and bring it closer to oem. i do the thermostat no issue. i saw i could problably simplify my vac lines a bit from how they were so i took the vac adv off the t it was on tied with the thermo sensor and sacs and egr sensor and give it its own line to the first port and put the rest of that junk on the second port and run my bov its own line to the third port. i reset the tps and isc and got out for a drive. it idled better and drove smoother...... until i got to the first stop sign where it immediately fell on it face. i start it back up and continue on my prarie nurburghring and then it starts sputtering like crazy once it hit boost. like it was missing really bad. then  it would go away and absolutely haul balls. when it would do a decent pull it would run the best ive felt the car but the other 2/3 pulls it would misfire like a machine gun in wouldnt budge. really weird as ive never had this issue with my car before. so i limp it to my shop and of course it died every time i needed medium brakes. i start thinking vacuum for some reason so im inspecting everything and all looks ok i replaced the firewall line for good measure today because i never did before. no fix. my boost gauge is show -12-10 something like that right in between 7 & 14 even when cruising making me think vac is a problem so i take carb cleaner to all my connections and i dont find any vac leaks, so then i pull my plugs and they look great! i put the dizzy line back how it was and put all that back on port 1 and capped 2 and leftbov on 3rd port. im truly running out of ideas and i have the only starquest ive seen in oklahoma so there is barely anyone that knows jack about these so im very hesitant to take it to someone i generally do all the work on my cars like clutches and diffs etc im not shy of hyard work and i have the tools.

 

any help is appreciated thank you guys!

[kev]

Wow, that was one detailed write-up!    

The first thing I would do is focus on that BOV.   I have a feeling it is opening when it shouldn't and causing unmetered air to enter the engine and creating your stalling issue.   I'm not sure your BOV type, but remove it, if possible, or unhook it and 100% verify it cannot open in any situation.  Then try it out for a bit to see if it resolves the stalling issue and really overall drivability.    I really have a hunch that this the problem.  I've also had issues with the third rear port not being sufficient enough for proper BOV operation.   I typically tap into the brake booster port or connect to the intake port in the 3/4 runner that supports the transmission on auto cars (there is a plug there on manual cars).    I really only use the 3rd vacuum port for the boost gauge.  

While you are focusing on the BOV, take the time to check all of your intake hoses/clamps/etc. to make sure you are not letting in unmetered air.   Just the slightest leak past the MAS will result in major drivability issues on these cars.  

I am a bit concerned about how long it was overheating.  Unfortunately, our heads don't handle much of an overheating event.   It may be prudent to do a compression test to verify you don't have any cracks (focus on cylinders 2 and 3).   Although, this wouldn't cause the stalling issue.  

 

edit:  I updated your post count to 50 to alleviate any issues you may have posting in the forums on here.   Back when this site was very active, we had posting restrictions to new members, which sometimes continues to cause issues.   

kev

[GoldStar]

I second the BOV; I had a very similar issue with a non-crushed DSM BOV, it wasn't holding vacuum at idle. I confirmed it by blocking the opening "horn" with my hand and watching the engine idle noticeably smoother. My AFR gauge also jumped from 10:1 to around 12-13:1.
Also FWIW I run my BOV off of a port coming off of the intake crossover pipe, it's never been the source of problems for me.

[_onions_Belt]

Update* I swapped out spark plugs and wires, I just went with some champions in a heat range of 7 and gapped to .38. Went for a test drive and holy cow. I got to floor my car for the first time in 3 years. Spun second and put a smile on my face. Full boost 3rd and I was going far to fast for the street so I turn around. Cars running better then I’ve ever felt it run. Get back to my shop let it run and cool down outside while I clean up. Get back into car and immediately dies when I go to hit the brakes leaving my parking lot. Then I pop the hood and see the ignition coil wire popped off… no biggie. Put it back on fire the car up and let it idle, touched the gas and it just spun off 1500 rpm like a rev limiter for 3 rotations and then would open full throttle, I play with it for a while and I look under the hood again and somehow my vac adv hose popped off or I forgot to plug it back in so I did. Car ran ok idle. I drive it home with it dying at every light or stop or medium 90* turn I had to make no biggie I just start it back up again like a funky auto start and stop feature oh well. When I’m in gear and hitting the brakes in low 3rd gear or anywhere in 2nd decelerating I can here it back firing and freaking out.. clutch in while braking and dies. But besides that car runs like a top and hasn’t felt better. I was running e3 diamond fire coils that aren’t gappable. With new plugs it’s feels great and sounds better as well. But what to do about this stalling while braking? Also when the car was having a fuss last night reverse was almost unusable, as soon as I would let the clutch out it would stall unless I kept revs up as hard as I could. I don’t believe this to be an issue with the bov I really don’t it’s never given me issue and it’s setup the way I got the car and I’m running hard pipes and my car runs no mas it is an 86 so it runs on pressure most on a closed loop on a super rich fuel map. 

[scott87star]

Vacuum leak from the brake booster?  Could be sucking in a bunch of air when you activate it via brake pedal.