Zetec Throttle Bodies Hard to Start?

[Al Navarro]

My car has always been a recalcitrant cold starter.



Once it's up and running, it's easy to restart. But from cold (and this weekend it was plenty cold) it was near impossible. I have an external fuel pump that I hear whir when I turn the key 1/4 turn...leave it there until the whirring stops (I assume that's when system is pressurized), then turn the next 1/4 turn.



Anyone else with a similar setup have similar issue? (I wouldn't call it a problem, just a nusiance.)<edited><editID>Al Navarro</editID><editDate>2007-02-26 12:01:26</editDate></edited>

[Boxologist]

not on throttle bodies, but the 7 started fine on saturday night. my fuel pump is constantly audible till i start letting the engine and exhaust take over noise duties! http://www.usa7s.com/aspnetforum/images/emoticons/hurray.gif

[slngsht]

Al, from what I remember at Skyline, it takes a couple of minutes for it to act normal, right?

[RDROCKT]

Al,

Most stock ECUs will turn on the fuel pump for a certain cycle and then shut it off. It does this as a safety function in the stock calibration. This does not signify that the system is pressurized, only that the time has elapsed. When you take the engine out of it's factory atmosphere and install a tank and pump without an anti-drainback valve (foot valve?), it may take more than a short run for the pump to actually pressurize the system.

Try turning the key on until the pump stops running several times to assure the system IS likely to be pressurized. THEN turn it over.

My $.02! Ask me how I know!

Chuck

[slngsht]

I'd tell you to try something, but it's not the safest thing to try http://www.usa7s.com/aspnetforum/images/emoticons/lol.gif If you swing your seven down this way, i'll try and see if that'll cure it.

[JohnCh]

Al,



Sounds like a mapping issue. What ECU are you using?



-John

[Al Navarro]

Thanks for the feedback everyone.



Mazda-You are correct sir. I generally have to sit in the car and keep the revs up around 3000 for a little while before it will hold its own idle down around 1000 RPM. Does your unsafe solution include shooting raw fuel into the trumpets?



Chuck-I will try that little trick the next time.



John-I've got the PecTel unit.



Oh, one thing I forgot to mention is that very occasionally, I get a backfire when starting. Perhaps I am flooding the engine a tad after the first non-start?

[slngsht]

Al, I think Chuck's fix would've addressed if your startup problem was very short.



Yes, my unsafe solution involves shooting raw fuel... but, instead of carb cleaner or something like that, I shoot a slight amount of propane in... although if you have multiple trumpets, that'll be hard to do.

Propane is already a gas, so it mixes in well.

If your engine speeds up momentarily when you shoot it in, then you're not getting enough fuel.

[JohnCh]

A few more questions. Has the car had this problem from the beginning or is this something that has grown progressively worse over time? Is the cold start okay if the air temps are high, or is it a reluctant starter even on warm summer days? If it is okay when the weather is nice, was your car originally setup in a warmer climate than where you now live?



Thanks,

John

[Al Navarro]

It's always been somewhat reluctant. But it MUCH easier to get it running in the summer than now (temp in NJ in mid 30s)

[JohnCh]

My money is on a mapping issue. Cold start is a pain to tune correctly since you really only get one chance per day to make a change and then see if you made things better or worse. I am not familiar with the PecTel, but the Emerald uses a startup enrichment table that affects the timing and fueling based on temperature. My guess is that your system has something similar. You may need to change that, or it could require getting into your main fuel or timing table, or altering the throttle position at idle, or your startup timing, or a combination of the above (like I said, this can be a pain to track down). Hopefully someone with PecTel experience will chime in.



-John

[slngsht]

I wonder what the maximum duty cycle of your injectors are.



It is possible your injectors are oversized, and under cold start your fuel pools. Just a hunch. Do you know what size injectors you are running and how they compare to others with the same engine?

[Al Navarro]

You know Mazda, that's the $20,000 question...I know that there was some issue with injector sizing on some of the Caterhams early in the Zetec program. I've always wondered if mine was one, but never followed through on pulling the injectors.



It would be great if someone with a similar set up could chime in...let me know what kind of injectors I should have, before I go through the trouble of pulling one to see what size they are.



Anyone? Anyone? Bueller?

[slomove]

You need this for Mazda's suggested test http://www.usa7s.com/aspnetforum/images/emoticons/biggrin5.gif

http://www.holtsauto.com/products/112.jpeg



Contains a lot of diethyl ether and raises an engine from the dead at arctic temperatures. But I am not sure if you can buy this (or the similar Holts Start Pilot) in the U.S.



And if you get too frustrated you can sniff it for a good night's sleep&nbsp;&nbsp;&nbsp;http://www.usa7s.com/aspnetforum/images/emoticons/ack2.gif



Gert<edited><editID>slomove</editID><editDate>2007-02-28 19:48:28</editDate></edited>

[Al Navarro]

Is that ether based starting fluid bad for the Mass Airflow Sensor? And should I spray it into the trumpets or just on the foam filter (if this is the stupidest question ever, feel free to beat me)?



I was going to try it this past weekend, but the weather prevented me from even getting the car out of the garage...I had to make about 6 passes with my snow plow to get the frozen sleet cleared from our driveway...then I did my neighbors' drives out of courtesy (it was pretty much near unshovelable in our neck of the woods...like shoveling sand).

[yellowss7]

Al, I don't have a zetec, but I do have the Jenvey Throttle bodies and I find that to start mine up, I do the same with the fuel pump, wait until it stops, then when I turn the key I lighly feather the gas pedal to help it fire up. Has worked well for the past 7 years and I'm still on the orignial banner battery, and with a 12.4:1 compression ratio that's saying something!



(I plan to get it out on Thursday or Friday as the weather forcast looks promising. I hope the 2 foot drift in front of my garage bay melts by then)



Tom

[slomove]

Is that ether based starting fluid bad for the Mass Airflow Sensor? And should I spray it into the trumpets or just on the foam filter (if this is the stupidest question ever, feel free to beat me)?



Directly into the trumpets. Obviously tricky if you have 4 of them. I suspect if you spray it onto the foam filter you will just wash out the filter oil and possibly cause a nice explosion in the filter (happened to me last weekend with a big bang and a plume of smoke just from the fresh spray of filter oil).

[JohnCh]

Al,



Don't worry about damaging your Mass Airflow Sensor -- you don't have one http://www.usa7s.com/aspnetforum/images/emoticons/wink5.gif You are either running a Throttle Position Sensor (most likely) and/or a a Manifold Absolute Pressure Sensor with the Jenveys.



-John

[Al Navarro]

Tom: the throttle feathering has generally been the case with my car. However, when it's been sitting cold, it's not so easy.



Gert: I've had those little back fires on start up before. I think it may be due to fact that I apply a little throttle on start up (see above) and there's a bit too much fuel when the spark goes.



John: Thanks for reminding me. I'm pretty sure I have the TPS set up.



THANKS ALL! IF it's warm enough this weekend, I'll roll her out and try the ether spray (Pyroil brand). If it fails, I'll try the ether on myself. http://www.usa7s.com/aspnetforum/images/emoticons/biggrin5.gif <edited><editID>Al Navarro</editID><editDate>2007-03-20 06:14:07</editDate></edited>

[JohnK]

Al,

&nbsp;&nbsp;&nbsp;Learn your ECU, and what your engine expects. There should be a setup instruction for your throttle bodies from the mfg. This part of tuning is mechanical and, within limits, affects mostly low RPM takeoff. Things have to be really awry here to cause significant problems. The Bosch Automotive Handbook, 5th ed or so, provides a wealth of information in areas areas of ECUs and how engines work.

I don't know how many models Pectel makes, but the one I've worked with has a cursor that shows you where you are in any map (spark, fuel, start fuel enrichment, . . .) real time, so you can see and try some things to experiments with what's happening re fuel.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;If you're not making black smoke when the engine's cold, you're probably pretty lean. You can't hurt your engine by running too rich, although it may cost you a few sets of spark plugs. (the tuner's golden rule: start out rich, plugs are cheaper than pistons) With the flash memory that the Pectel has, you update your calibration as you make changes (read the screen on the laptop and the instruction manual - online help may be sufficient).

&nbsp;&nbsp;&nbsp;The work req'd to learn about this is well worth the effort. Without pulling teeth, I got a big lug of a 427 aluminum engine to start cold (40 F) with very little throttle and it would tick over at low RPM - and settle down to a nice idle once warm. It's not rocket science or brain surgery but takes a bit of study. For getting power, THAT is a lot of work and needs a dyno.

Cheers,

John K

[Al Navarro]

http://www.usa7s.com/aspnetforum/images/emoticons/hurray.gif

It was warmish and sunny today, so I decided to give it the old college try again. I did use the Pyroil starting spray and on my second attempt got the car to catch and stay running (with the aforementioned semi-delicate feathering of the throttle).



At first it felt like the engine was firing on 3 cylinders, literally. But then a few "pop-pop-pops" out the side exit and the old Zetec that I know and love was back. So I went out for a about an hour-long blat and reconnected with everything we love about these little cars. Thankfully, there is no "but" to the story.



John K - I am 100% mac-based, so doing my own ECU tuning isn't as easy as it is for some of your PC-based folks. However, I will try and borrow a laptop sometime this year to sit down and do exactly as you say.



Thanks again everyone for your suggestions and patience with my ignorant "does Al even know a thing about these cars" questions!!!<edited><editID>Al Navarro</editID><editDate>2007-03-24 11:04:17</editDate></edited>

[JohnK]

Al,

HooRah - another wise soul who avoids Micro$oft - unfortunately one does work at the mercy of the software developers.

You don't have to be any kind of a wizard (my training is as a Biologist) to understand how to make your car run well, but it does take a bit of thought and some patience. The computer gives you so much control and makes it so easy to make and observe change, it's actually easier than in the 'good old days'. Me looking back 40 years trying to get my Ducati running and still mystified as to how that old DelOrto worked. Pushed that @#$% motorcycle all over the neighbourhood.

I will make a pretty confident guess that all you need to do is find the table that says that it's what the engine reads when the engine's below running temp and bump up the amount of fuel that it delivers in that state. Spitting back out the carbs is typically a sign the engine's not getting enough fuel. The worst you can do here is foul a set of plugs, and from what I've seen, that's not all that likely. Best of luck - at least your Se7en's running - I've got another year or so before mine will be ready to go. Enjoy the Spring and its weather.

Cheers,

John K











&gt;&gt;John K - I am 100% mac-based, so doing my own ECU tuning isn't as easy as it is for some of your PC-based folks. However, I will try and borrow a laptop sometime this year to sit down and do exactly as you say.

[slngsht]

>Clicky (http://www.vidvoting.com/xoops/modules/xstreamer/index.php?class=video&id=16)



http://www.usa7s.com/aspnetforum/images/emoticons/rofl.gif



http://www.usa7s.com/aspnetforum/images/emoticons/leaving.gif

[roll a 7]

I have a Pectel T2 with Jenveys on my zetec. It was programmed some years ago but starts reliably, although it often takes two tries when cold here in San Diego; cold being relative(!). As I recall we set it to give extra gas @ the 500 RPM level and also advanced the timing some to prevent stalling/dieing. The map has a noticeables spike @ the 500 and 1000 RPM levels. Some experimentation should produce a better solution. If I find the map I'll provide more flesh on these rather vague guidelines.



Marren Fuel injection has helped some of us figure out what injectors to use. Tim Marren can be found on the internet and is located in NJ, I think.

[slngsht]

Marren Fuel injection has helped some of us figure out what injectors to use. Tim Marren can be found on the internet and is located in NJ, I think.



Holy Cow!



Tim Marren!



I bought some injectors from him in the early 90s. I can't remember what I had for breakfast. I don't know why I remember that http://www.usa7s.com/aspnetforum/images/emoticons/willy_nilly.gif

[Al Navarro]

The new SOP for starting my car cold:

1. Turn key so "accessories/ancillaries" are activated (including fuel pump).

2. Repeat 3 times.

3. Give throttle one squeeze, then release.

4. Turn key all the way to engage starter motor with light throttle pressure.

This has pretty much been my fix for the cold start problem since I came back from the Dragon. Works 80% of the time. The other 20% require just a little more coaxing. Still have not remapped ECU. Will wait until I do the head work.

[SR27.Seth]

I will make a pretty confident guess that all you need to do is find the table that says that it's what the engine reads when the engine's below running temp and bump up the amount of fuel that it delivers in that state. Spitting back out the carbs is typically a sign the engine's not getting enough fuel.
.

I think I would look at what information the ECU is reading before trying to change cold start maps. EG: Does the resistance in the coolant temp sensor (measured at the ECU) match the spec? Go through all of your sensors (computer inputs) and compare readings (be it voltage signal, wave, or resistance) to a reference, before you try to change any mapping. Remember an ECU is only a computer: GIGO.

[ottocycle]

Al,
I just read your post. I think your cold start (choke) map needs adjusting. It should be a little easier to do than idle, midrange or top end adjustments as it need not be too precise. It is only needed to ease initial ignition and will be bypassed when the engine heats up. Your existing map will take over once a certain temp is reached. When you get it remapped after you do the headwork tell them and they will bump up the values. Try and find a shop who have worked with your system. While the principles are the same for all programmable systems, you do not need to pay the tech guy to learn the details of your system. If you know who markets your system in the U.S. they might be able to steer you to a dyno facility near you. Remember a dyno is only a tool/gauge. It is only as good as its operator/interpreter.
Cheers,

Dermot.

[gjslutz]

I would think the back fire would indicate lean mixture. That along with the fact you need to hold higher RPM till warmed up would make me think that. My Zetec with the Emerald ECU and Raceline TB’s has no cold problems, although it has only seen 40’ during the time I owned it this past month. If you are uncomfortable with adding fuel, you could try to hand choke (reduce the air) into the TB on starting cold. Anything to block the air should work. Then as above it would be the ECU problem to solve.
Gary

[gjslutz]

Al,

Now have been starting up mine in the low to mid 30's. At times if I don't touch the gas Pedal it will start & die the first time. At times it will also do a lean pop (backfire) on starting. It idles smooth after 15 seconds after starting.

Gary

[Kitcat]

Start & die? Never had that problem with my Crossflow:).

[JBH]

At 25 F, my car would not start. It would catch briefly then die. It did this until the battery ran down. I borrowed a battery and then it wouldn't even catch. We tried choking it, ether, etc. I pulled the plugs to find a lot of carbon. I changed the plugs and it started, albeit reluctantly. By now it was 42 F.

I have tried Al's procedure, but it makes no difference. Temperature makes a big difference - it has to be fuel vapor pressure - indicating my startup map is too lean.