still burning too much gas...

[MrMazda92]

I love Costco, I need to get a new membership.

[Mr.mx-3]

theres some steps in the online manual on how to check the injectors electrical components, but im fairly sure youd need to remove them from the car to get good access to them. however if they are out of the car they are fairly easy to test. to test for leaks you need to pressurize them and see if they leak, to test for clogs you can plug them into the car and set them onto 6 glass jars with one injector in each jar and having someone try and start the car. youd then watch the flow/spray from each injector should be more or less the same. you could also measure the amount of fuel sprayed into each jar over a set period of time which would tell you flow rates. but dont be an idiot, vaporized gas is extremely flamable, no smoking or sparks anywhere close to you preforming this test. unplugging the disty would be a good idea as wel.

that being said theres more then one cause of a dead cylinder. are you getting spark on it? a compression test would tell you if the cylinder is healthy, and if it is its more then likely not firing from a clogged injector or no spark. is the spark plug in that cylinder wet/smell of gas? if it does thats an indication of bad compression or lack of spark or that cylinder being flooded.

to everyone else. i was just thinking. is it possible for injectors to dump too much fuel if they arnt leaking? i guess the only way to know for sure is to take them out and bench test like i described but i guess thats another possible cause of my problem. ive read its possible for 1 or 2 to become partially clogged and the other injectors will try and compensate by adding fuel to correct the lean reading in the o2s, but if this was the case id expect the spark plugs of the corresponding cylinders to look different from the others no?

Thanks. I pretty sure it's not a compression problem the plug on that cyl. is was compleatly dry and looked new as in just like the day I put it in new with no smell of anything gas/oil while the others have a orangeish tinge to them and smell of gas. That's why I'm thinking there was no gas going into that cyl.

You also mentioned something about the other disty you put in made your car seem more powerful I noticed the same thing happened to mine after I put in the new disty on mine But I also put in new spark plugs. I'm glad to hear you are working out everything on your car it can be a slow and mind wrecking process sometimes..

[davmac]

Get the coolant temp sensor corrected before all the other plans. I hope not, but it may be a wiring problem in your harness. The DTC and fuel mileage symptoms point in that direction. A bad connection will send an infinite resistance signal and cause the DTC. I'm kinda confused that you're testing voltage. The 2 important sensors are RTDs and they send a resistance signal. 3 sensors: 1 for fuel / air control, 1 for radiator fan control and 1 (1 pin) for gauge. The 2 2 wire sensors are not interchangeable - they produce different signals. I believe the gray one is the fuel / air mix signal. Rockauto has them for $30. Looking at Mazda parts it gets more confusing as the 92-93 models list 2 2 wire units use part # FS0118840 and B3C818840 - I'm not sure which is which. But online Mazda parts dealers are charging around $30 usd for any of these.
All I know is that the ECU will be looking for a specific signal range.

This is why air in the coolant will cause surging / bouncing- or high idle.

Maybe I didn't read carefully but nothing here points to bad injectors. Bad injectors cause misfire and it is obvious. I know this is really frustrating, but troubleshooting is really isolating and correcting 1 thing at a time. Good luck.

[mikeinaus]

coolant sensor is fixed. the two i got from amazon happened to be defective. the beck Arnley one that i got locally is working fine and my idle is perfect now. i also thought it was a problem with the wiring but it just didnt make sense from what i was observing. i know the sensors work off of resistance. but the ecu receives a signal in voltage that is relative to the resistance of the sensor at any given temperature. lets say at 0 resistance the ecu is sending 12v on that wire. as the temperature increases the resistance of the sensor increases and lowers the power output of the wire. operating temp yields a voltage around 2.6v if i remember correctly. the ecu reads this by basically having a voltmeter attached to the wire and measuring the drop in voltage. the sensor is tested by measuring resistance at a given temperature. i believe the delpi sensors i had were just calibrated wrong as the readings they produced were smooth and linear to the increase in temperature but they were not in spec of what the ecu wanted resulting in a code to pop up once the coolant reached a certain temperature.

ive read its possible for a fuel injector to become partially clogged and have a poor spray pattern and lower flow then ideal. since we have 2xo2 sensors and 2x3 injector banks per o2, if 1 injector is bad the 3 cylinders on that rail will report a lean reading on the o2 sensor. the ecu will then adjust more fuel to that bank to try and correct the problem. that would in turn cause 2 injectors to run rich and 1 to run lean with the computer thinking it has an ideal mixture. its possible my injectors are good but without having a bench to actually test them on or get them flow tested its worthwhile for me to just replace them with known good ones to eliminate them as possible causes. its not like i have much else to go on at this point in time. im also replacing the fuel pressure regulator. by doing this my fuel delivery and ignition supply have been more or less completely replaced.

air filter and my cat are not clogged, my o2's and temp sensor are new and my vaf is working properly. once my injectors are replaced that is more or less everything the ecu uses to detect and adjust fuel mixture. if im still having problems at that point im going to look into my knock sensor. its possible to ecu is falsely detecting knock and retarding the timing, ive herd this is possible without throwing a code depending on how severe the knock is. when i get to that point if i still have problems ill move onto a kl36 ecu. at that point in time if im still having bad mileage im going to take a big hammer and smash my car into tiny pieces as there is no possible excuse for it to run improperly when every aspect has been tested and replaced.

[mikeinaus]

i did a bit more testing at school today. my fpr is in spec as well as the rest of my fuel delivery system. i didnt bother removing the fuel rail and testing my injectors as i have a new set on the way. i also noticed my evap solenoid wasnt hooked up to a vacuum. ive now fixed that which should help in emissions slightly. i however dont believe changing the coolant sensor had a significant impact on my fuel mileage. i havnt filled up since i replaced it but ive put on about 112km and im sitting at slightly more then 1/2 a tank which is on par with what ive had lately. i also hooked a voltmeter up to my knock sensor and it didnt look like there was any odd readings. there were no specs on how to test it on alldata or mitchellondemand but the voltage coming off of it was steady and didnt change with revving the engine. that being said the wire going to the plug has been cut and butt connected back together which cant be great for it, but i doubt its reporting knock and causing the ecu to retard timing.

does anyone know of a way to monitor what the ecu is telling the disty in reguards to advancing or retarding timing? it would be interesting to tap into that and watch it on a test drive and verify if its advancing timing at higher rpms...

does anyone know of any internal engine problems that would lead to burning too much gas? i have a strong vacuum at idle, idle is smooth and my compression is decent across all cylinders (kind of low 180psi, but even). no significant vacuum leaks that i can find, and the engine is clean below the valve cover with barely any oil loss between oil changes.

[mikeinaus]

12.78l/100km with the new coolant senor. i was being fairly hard on the throttle at times and driving more aggressive then usual. id guess with Conservative driving i would probably be a litre or so less per 100km, so theres been a small improvement. lets hope the injectors give me an ideal burn, as ive run out of things to try. im afraid my only option other then ms at that point would be an adjustable fpr and dialing back the fuel pressure. dangerous especially without a wide band but i cant think of any other way to dial back the excess fuel being injected. please please please be the injectors.

[Nd4SpdSe]

Unless it's a problem with the ECU, Megasquirt won't magically fix what's wrong. Megasquirt is a system that's much more advanced than the stock ECU and unlocks potential of your motor and give you control to tune it in a way to suit your needs and mods. Megasquirt won't fix your issue. I want to say that maybe Megasquirt may help pinpoint the issue, but I would also be concerned that installing Megasquirt may actually make it harder to pinpoint your issue.

[mikeinaus]

i was thinking it would give me the ability to physically inject less fuel and create an ideal mixture. however the o2's are reporting an ideal burn so it would kind of be like tuning in the dark. it does make sense that the injectors could be bad. sadly its the only thing i have left to go on. i did however find this which backs up possible clogged injectors.

FAILURE 2...Injector filters become clogged.

CAUSE OF FAILURE 2..."Foreign particles" in fuel tank(s) or fuel lines, or fuel rail. Foreign particles in almost all instances, will be rust. Larger rust particles may be collected within the injector filter, or the fuel filter, and reduce fuel flow. Microscopic rust particles may also pass thru the injector filter, and cause the spray pattern to alter, fuel flow to alter, and/or the injector pintle to not seat properly. This is a common problem on vehicles that have sat unattended, or suffered from lack of routine maintenance. Incorrect fuel tank fuel filter; holes/tears in fuel tank fuel filter; breakdown/degradation of interior wall of fuel supply line; breakdown/degradation of interior wall of fuel injector hose, and rust in the fuel rail.

EFFECTS OF FAILURE 2...the injectors leak at the pintle and/or the spray pattern is altered, and/or the fuel flow is altered. Lack of engine power from underfueling; potential for engine overheating; remaining injectors/cylinders are overfueled to compensate for underfueled injectors/cylinders as the "closed loop" O2 system attempts to maintain stoiciometric ratio.

also goes on to talk about misaligned injectors or deflected spray patterns

EFFECT OF OFF-ANGLED SPRAY PATTERN
(relevant reading)



Fuel injectors are manufactured to spray fuel in a direction that is parallel to a line from the centerline of the filter bore (at the top of the injector) to the centerline of the injector pintle (at the lower end of the injector). That is, the fuel spray pattern should leave the pintle end of the injector as though it was fired from a gun...in a straight line. (Forget about trajectory angles...think straight line.) In doing so, the fuel spray hits its designed target at the exact target location on the back side of the intake valve. The engineering designed effect is to vaporize the fuel that has been atomized by the injector, by fuel hitting the hot intake valve. Recall, that the greater the atomization of the fuel, the smaller the diameter of the fuel droplet, therefor...the smaller is the overall fuel droplet surface area, and the fuel droplet approaches the ideal size to be totally burned, as it mixes with the available air intake. If the fuel droplet does not reach a size, such that it is totally burned, then the unburned portion is exhausted . It is not uncommon for clogged injectors to have an off-angled spray direction by 5 percent. While this may not seem to be a large degree of error, consider the following. On a 1984 XJS V-12 HE, the distance from the pintle seat of the injector to the back side of the intake valve is approximately 4 7/8". If the injector spray angle is off by 5%, then the fuel spray misses the target location by 15/32" ( almost 1/2" ). Depending on the direction of the off-angled spray, the fuel will either hit the intake valve stem, the outer lip of the intake valve, or in more severe cases, the wall of the intake. Furthermore, if the injector is fitted with a lower seal ...(a seal between the injector and the intake manifold), and that seal has become deteriorated, or collapsed from age, engine heat, or both, then there is a probability of the injector fitting in the intake at an off-angle, which may produce the same off-angled spray pattern effect, or exacerbate an already off-angled spray pattern, as well as the probability of an air leak. The result, in all cases above is ... fuel wetting or (puddling) on the valve stem or the intake manifold wall ... a decrease in fuel droplet surface area... a decrease of fuel vaporization... ... a decrease in total fuel burn ... a loss of HP ... a decrease in fuel economy ... and reduced performance. Does an off angled spray pattern matter? Yes. Will dirty injectors or deteriorated seals cause off angled spray patterns? Yes. Is it important to have clean, and maintained injectors? You decide.

however my teachers point of view is that if an injector isnt leaking and they are pulsing properly there is no way then can be bad. he goes on to say that im acting like a "canadian tire" mechanic and that if i just replace parts that ill never make it in this trade, and that i need to use my brain to find the cause of problems. its all very funny because whenever i ask him what could possibly be the cause or what i should check out he replies with "you car is modified, it can be anything. put your car to stock then you wont have problems". im really hoping they fix the problem, not just for fuel savings, but to have a massive i told you so grin when i tell him. he is in many ways a great mechanic, but he is a bad teacher and is very stubborn. you should hear his philosophy for giving practical marks. lets just say were expected to know how to do everything being PRE-apprentices and that if we have to ask any questions we should loose marks. my latest project ive been stuck trying to figure out an oil leak on a 97 accord and i have a group of 3 kids that have never touched a car before. try replacing a rear main seal when everyone in your group is useless and you get in trouble for working on the car because the kids need to learn how to use a wrench. as far as im concerned pulling a tranny is not for beginners, they should learn on brakes or oil changes before attempting an advanced procedure like that. the idiots put all the bolts in a massive pile and didnt sort or label anything. when the time came to put it back together guess who had to go threw everything and try and figure it out... RANT

right now im guessing im burning around 30% more fuel then i should be, misaligned/clogged injectors could make up for that 30%. it also makes sense they could have been contaminated with rust on the engines journey from japan. as far as i know solo_ryder never had the car sit for an extended period of time.

[Ryan]

Your teacher is right.

First thing you should do is find a stock KLDE ECM. I've found the chips give the mileage you suggest, so it doesn't surprise me

Check your compression. If the motor needs to run a higher duty cycle to do the same work, it will burn more fuel than its supposed to.

[SuperK]

well, you got some injectors on the way to you... but I got a funny feeling until you try another ECU or ECU/VAF combo (depends on what ecu you get) it's still gonna be the same story. Bestoluck to ya, I hope you're able to use that "I told you so" though!

[whitete]

keep us all updated , im still working on my misfire , but i believe its related to valve sticking or cracked retainer.

any news on the issues yet ?

[mikeinaus]

Your teacher is right.

First thing you should do is find a stock KLDE ECM. I've found the chips give the mileage you suggest, so it doesn't surprise me

Check your compression. If the motor needs to run a higher duty cycle to do the same work, it will burn more fuel than its supposed to.

compression was 180 or 190psi across the board. i dont remember exactly which but they were all more or less even. a de ecu/vaf is going to cost $60 + an hours drive each way to the wreckers (probably $30/40 worth of gas). im going to see how the injectors turn out then ill probably just grab a kl36. theres no point in wasting $100 on temporary parts just for diagnosis when for slightly more i can get an ideal ecu. by the time my injectors get here i should have enough to grab a kl36 anyways. its a slow process, im just hoping it works out in the end. and its not just about my mileage, as is my car wont even come close to passing emissions, is that standard with the chips? i was under the impression a kl36 only gave a 5-10% max increase in mileage over a chip.

[SuperK]

Here's the thing about high-flow cat's...

Their meowing capacity is OUTRAGEOUS!

I mean, they're not worth a damn when it comes to doign what a catalytic converter is supposed to do. Most likely it was a cheap "High-flow cat" purchased which last 1-2 years then flat out fail. I bought what I thought was a good brand catalytic converter (magnaflow) and 2-3 years later it did absolutely nothing. I failed my emissions on a b6DE so bad, it wasn't even funny. I was in the 600's whereas I was supposed to be 130-ish. I have seen many ZE's pass emissions and I would say it's mostly to do with the cat properly doing it's job. My cat even had stupid "certifications" for emissions or something like that.
but you get what you pay for. a "performance" converter for less than 100 dollars, is, for the most part, crap.

This is my personal experience and will vary by setup and situation.

[mikeinaus]

i was failing on HC not co. hydrocarbons is unburnt fuel. cats deal with burning off excess co. i guess its something that im only failing the one aspect, but what i am failing has to do with burning way too much gas. or not burning it for that matter.

[Pritchett]

Doesn't the ZE with the stock ecu run rich due to the larger injectors? Or do the narrow band o2 sensors correct this problem fully?

I also run only 1 coolant sensor in my 93 ZE , is that causing me to burn more fuel? I'm at the 250km per tank mark as well, but I'm always flooring it.