hello i have an 87 s4 na and i just put 2 mass's and a fuel pump in it trying to get it to run right but no good, its getting good fuel pressure but it acts like its not getting enuf to run right like i step on the gas and it falls on its face and trys to die and when i let off it backfires.... it will rev up if i slowly press the gas to about half way but any more then that it falls on its face.... if i put my hand over the inlet on the mass i can go full throttle and if i spray carb cleaner or brake clean in the mass it will rev out great (i know carb cleaner and brake clean aint good for rotarys its just im desprate!!) idk what to do now i have an ecu on its way hoping that will fix it

its got a new tps, fuel pressure regulator, new 02 senser, and a new fuel pump + 2 mass's..... the PO put the tps, fpr, and o2 senser in idk what to do any help will be greatly apprishiated thank you

sidney

also if anyone live near Parkersburg WV or Belpre OH and might beable to help out it will be awesome if you can thank you PM me if so

 

sorry about spelling theres a reason im not a teacher haha

 

sorry about the multiple posts but also i cant get my shops diagnostics computer to work on the car idk its killing me....

 

theres a code check plug up twd the front of the shock tower,i believe its green,look in the faq section at top of 2nd gen archives,if its not there try the search,another possible area to look into is the vehicles grounds,from what i understand bad grounds cause alot of problems on these cars,when you swap the ecu im sending you even then you need to check all connections and grounds in that area,even where the ecu case is bolted down,its always corroded and rusted in that area steve

 

for sure ill check them out when i get the ecu and what grounds should i check? all thru out the car? cause idk where they all are lol

 

Try replacing the fuel filter sock on the bottom of your fuel pump, is it a used one?. Solved my problem, not even mentioned in the Haynes Manual, $10.00 each from your Mazda dealer, buy 2, one as a spare. You cannot flush them out, replace them.

 

replaced with pump...



edit: lol carbs are so much simpler haha i think i might have to stick with fb's ;p

 

try first the engine to grounds,may be several,harness to grounds,they shouldnt be hard to spot,look for those bare eyelet connectors ,they will be bolted to the chassis,alot of people even add extra grounds,another good idea is to buy a can of electrical parts cleaner,you can spray on various plugs,connectors,etc.

 

for sure thx man will do lol idk how the grounds can make it act this rediculasly tho its like at an idle its running rich black smoke but it wants to die when you get on the gas but its fine when you gots your hand over the air flow meter or a can of flamable substance spraying in the intake its messin with me haha

 

I just had the same problem and still do until today when I set the tps for the millionth time using all the methods and it seems to be working now. Before at up to half throttle it would redline but at wot would fall on its face at any rpm. Now after today it definitely does not do this anymore. Just a suggestion try the tps again might work for you

 

for sure

 

Has to be asked...does the engine have good compression?

 

Air intake leaks causing lean running conditions?

 

i second the tps, same problem, but instead of adjusting it, before the problem arose i had just removed my uim. Read a post about the contacts being bad on the tps harnes due to corrosion. Disconectted the wire harness and saw nothing but the blue. Got a flat head and scraped the male and female sides, reconnected, problem solved! By the way it always fell flat on its face whenever going above 1500 rpm

 

if it didnt have compression it wouldnt idle the way it does the idle is great now that i started playin with random stuff and put the diff mass on it.
havnt checked will tomorrow
for sure will do hopefully tomorrow depending on if we can get some cars done at the shop

 

problem fixed it was the ecu and the tps wasnt set runs beastly and thanks to FCinWV the tps got adjusted that kid know his stuff!

EDIT:old ecu was bad!