Elanscan shows low boost

[PECKHS]

Hi, this is the first proper elanscan that I have done since my engine rebuilt. I thought I have eliminated most of the problems (or at least I think i did), but going through some of the readings it does not seems to be so.
I realised that the boost peaked at about 0.325bar, power was only barely 80hp. I was pretty sure I read the boost to be about 0.5bar from the gauge.
From reading another thread, I realised that the scan will not show an accurate boost reading as I have a 3bar MAP.
Can someone please please kindly help me take a look at the scan as I am not good at all in intepreting the readings.
I really do need to get the elanscan on the road after so many months.
Thanks.

So here's the scan:

30042011a.zip

[GeoffSmith]

You need a 2 bar sensor as this is used by the ECU to set the fuel mix - the 3 bar sensor will tend to run lean and may cause damage at high levels of boos.

I haven't had long to look at your files but:

a) Correcting for the 3 bar sensor, you are getting about 0.6bar of boost as you've seen on your gauge.

b) You only get maximum power at 100% throttle and maximum revs. You are reporting ~ 75hp at 60% throttle and 4000RPM which is reasonable. You were either light on the throttle (probably a good idea until you get a 2 bar sensor) or the TPS needs adjusting: connect up ES and press the throttle with the ignition on (no need to start the engine) and you can see if the reading is close to 100% with your foot to the floor.

[rip]

You need a 2 bar sensor as this is used by the ECU to set the fuel mix - the 3 bar sensor will tend to run lean and may cause damage at high levels of boost.

....
Unless you are using injectors with 50% bigger capacity.

These are controlled by on/off pulses.
The 3 bar MAP sensor scales all readings down by a factor of 1.5 so this will cancel out the bigger injectors & you should get correct fuelling.
The whole point of these together is that the stock (& Everest) ECU settings set overboost at slightly under 1 bar because the standard injectors cannot supply any more fuel to cope with any more. The bigger ones can.

Correcting for the 3 bar sensor, you are getting about 0.6bar of boost as you've seen on your gauge.

But how did you work that out?

What I did was to add boost to atmospheric pressure (1 bar) to find MAP. I believe ES does the reverse to calculate boost.
0.325 + 1 = 1.325

Compensate for the 3 bar MAP sensor by multiplying by 1.5 (3 bar / 2 bar)
1.325 * 1.5 = 1.9875

Then take away the 1 bar I added earlier
1.9875 -1 = 0.9875

So I got 0.9875 bar of boost, not 0.6.

There are some values in ES's protocol.ini file you can adjust to modify the readings to cope with a 3 bar sensor. They'll be in this section of the forum. I'm sure you'll find them with a search.

So you are actually getting 0.98 bar of boost.

[GeoffSmith]

Correcting for the 3 bar sensor, you are getting about 0.6bar of boost as you've seen on your gauge.

But how did you work that out?

First off: Typo, should have read 0.5bar as PECKS said his gauge read.

Following your reasoning:

Add boost to atmospheric pressure (~1 bar but read as 0.7 bar by the 3 bar sensor when the ignition is turned on - displayed as a constant Barometer reading) to find MAP.
0.325 + 0.7 = 1.025

Compensate for the 3 bar MAP sensor by multiplying by 1.5 (3 bar / 2 bar)
1.025 * 1.5 = 1.5375

Then take away the ~1 bar (0.7 × 1.5 = 1.05 bar) added earlier
1.5375 - 1.05 = 0.4875 bar

Alternatively 0.325 × 1.5 = 0.4875!

There are some values in ES's protocol.ini file you can adjust to modify the readings to cope with a 3 bar sensor. They'll be in this section of the forum. I'm sure you'll find them with a search.

Don't think the latest versions of ES use the .ini file any more - there ain't one on my pc and it works OK.

[saska]

Correcting for the 3 bar sensor, you are getting about 0.6bar of boost as you've seen on your gauge.

But how did you work that out?
What I did was to add boost to atmospheric pressure (1 bar) to find MAP. I believe ES does the reverse to calculate boost.
0.325 + 1 = 1.325

If you look on the scan the atmos pressure is listed as 0.7 bar which would be 1.05 bar with a 2 Bar Map. Think about how the MAP works -- it takes a given pressure and converts it into an electrical voltage. A 2 Bar MAP will produce a greater voltage for a given pressure than a 3 bar MAP will. The ECU & Elanscan think this voltage is coming from a 2 Bar MAP when in fact it's coming from a 3 Bar so it thinks pressure is lower than it is.
I suspect the way Geoff did it was subtract atmospheric pressure (0.7 bar) from the boost (1.325 bar) to get 0.625 Bar

[rip]

Add boost to atmospheric pressure (~1 bar but read as 0.7 bar by the 3 bar sensor when the ignition is turned on - displayed as a constant Barometer reading) to find MAP.
0.325 + 0.7 = 1.025

But I believe ES is calculating boost by subtracting 1bar from MAP, so if it says .325 bar boost, then wouldn't this be 1.325 MAP? Then because it is a 3bar sensor, it should be 1.325*1.5 = 1.9875

Geoff, instead of discussing it here, can we do some sums over a drink or two at Castle Combe?

[PECKHS]

Hi guys, really don't mind you discussing over at this thread. Many of us will benefit from your discussion. Keep it coming please
I do have a 3bar MAP, however I do not know if I have a higher capacity injectors. Can we tell from ES?
From what I have learnt in LEC, if I have a 3bar MAP and normal injectors, the ECU will indicate a Fault Code 44. However, when I did the paper clip test, no fault code was flashed. I don't seem to see a lean running engine fault code registered in ES too. Or maybe I was not looking hard enough?

This is what I have now:-

Haltech 3bar MAP



this is what I got from Rocksauto when I ordered a Beck/Arnley. However it does not work and when fitted my elan couldn't even start. I tried searching for more information on this MAP but nothing came back..



ordered another from sjsports but for some reasons unknown it has not been send after 1 month

would appreciate if I can be enlightened further

thanks

peck

[Monty]

Take a picture of the Injectors, we maybe able to tell if there stock or aftermarket

[PECKHS]

Ok, I will try to take a pic of the injectors. Tks

Peck

[PECKHS]

ok, these are the best pictures i can take of the injectors without removing them (not technically inclined enough to remove them)
Can't really tell, but from the looks it seems to be the originals.





so, I know I have a working 3bar MAP. Should I just get a set of biger injectors instead? maybe from here ?? http://www.rceng.com/
if I do, which cc should I get? seems that the PL8-0550 is popular upgrade in LEC.

Tks

Peck

[Monty]

They do look like stock Injectors, btw they are a pain to remove

If your sticking to boost under 1bar then you just need to go back to the 2bar MAP sensor, my question is why was a 3bar MAP fitted in the 1st place, has there been any work done to the Turbo ie a hybrid (to get more boost)

[PECKHS]

They do look like stock Injectors, btw they are a pain to remove

If your sticking to boost under 1bar then you just need to go back to the 2bar MAP sensor, my question is why was a 3bar MAP fitted in the 1st place, has there been any work done to the Turbo ie a hybrid (to get more boost)

well, long story. this car was not driveable when i bought it. overhauled the engine, and bobrown helped me to get a used turbo and overhauled that too ...
prior to that, it was in a workshop that has no idea what's wrong with the elan, for about 3 months...
i've no idea why the 3 bar MAP was there

what i wanted to know, is why there was no code 44, and the ES doesn't seem to show any lean running ???

thanks

peck

[rip]

what i wanted to know, is why there was no code 44, and the ES doesn't seem to show any lean running ???

peck

Because it does not know.
The ECU is reacting to the value being sent back by the MAP sensor. It calculates the correct amount of fuel for the amount of oxygen it is programmed to believe it is inducing into the engine. It is unaware that this is 2/3 of the real amount of oxygen.
Larger injectors would make it inject more fuel in exactly the same way so the 2 cancel each other out.

[GeoffSmith]

But I believe ES is calculating boost by subtracting 1bar from MAP, so if it says .325 bar boost, then wouldn't this be 1.325 MAP? Then because it is a 3bar sensor, it should be 1.325*1.5 = 1.9875

If you put the curser on, you can see that the Boost is reported as the difference between Manifold pressure and Barometer whenever the former exceeds the later.

what i wanted to know, is why there was no code 44, and the ES doesn't seem to show any lean running ???

Under normal (no boost) conditions with the engine warm, the ECU goes into closed loop running and the O2 sensor oscillates between ~0.5V and ~3.5V so the fuel mixture is correct. When the engine (strictly speaking the O2 sensor) is cold or when there is boost, everything goes open loop and the ECU fuels (rich) according to its lookup tables. Normally, the mixture will be rich and the O2 sensor will go high but if it is lean, the output will go low and the ECU will detect and display code 44. Your O2 output is marginal (but slightly lean compared to a normal scan) at the level of boost you were getting so code 44 isn't displayed and more importantly, you are not running lean (with the potential for burned out pistons).

Normal (rich) fuelling under boost.gif

Abnormal (lean) fuelling under boost.gif

[PECKHS]

Ok, I think I'm beginning to understand.
The reason why there was no code 44 was because I was light footed when I did the trial run. If I was to do a WOT fault code 44 will probably surface as the air will be insufficient for the fuel during WOT.
I have today receive an email from rockauto that they have send out the MAP. I should be receiving it early next week. I ordered the DELPHI Part # PS1007511B1. Hopefully they posted the correct part this time round.
Will re-do a trial run again when it arrives and fixed.
Thanks guys.

Peck

[GeoffSmith]

I'm still mystified why your MTE-Thomson MAP didn't work, although I did find a nice catalogue with lots of pictures and cross references. If you've still got it, what about plugging it in (electrical only) and seeing what barometric pressure ElanScan is reporting back?

PS Have you peeled the Haltech label off yet to see who actually made their 3 bar MAP sensor?

[PECKHS]

:smt023

I'm still mystified why your MTE-Thomson MAP didn't work, although I did find a nice catalogue with lots of pictures and cross references. If you've still got it, what about plugging it in (electrical only) and seeing what barometric pressure ElanScan is reporting back?

PS Have you peeled the Haltech label off yet to see who actually made their 3 bar MAP sensor?

the only inforamtion i found for the MTE-Thomson was in brazilian(i think). couldn't understand a word, and no specs available. I still have it, will probably try plugging it when I receive my delphi next week from rockauto.

And I have never thought of peeling the sticker off the Haltech. WIll do it next week and let you know.

Cheers

Peck

[tigerdog]

I think you really need to get to the bottom of your fueling system. From the photos, the group here has concluded you have stock injectors. You clearly have a 3 Bar MAP sensor. If you also have a stock fuel-pressure regulator and stock ECU, the combination is trouble.

Marie is correct: changing only to a 3 Bar MAP without changing injectors (or raising fuel pressure to compensate) will cause the engine to run very lean. This is a dangerous and potentially expensive setup! If you have confirmed stock ECU, injectors and fuel pressure, please change back to a 2 Bar sensor.

If you plan to run less than 1 Bar boost (like any of the mountain chips) there is no reason to have a 3 Bar sensor in the circuit. If you must keep the 3 Bar sensor, then your only options are bigger injectors (RC 550cc are the usual choice) or maybe raising the rail pressure to increase flow though I haven't seen this done. The 3rd option would be a different ECU, calibrated to make up the difference between 3 Bar MAP and stock injectors.

[GeoffSmith]

this is what I got from Rocksauto when I ordered a Beck/Arnley. However it does not work and when fitted my elan couldn't even start. I tried searching for more information on this MAP but nothing came back..

Peck,

I think I've cracked it and I'd be interested to know which MAP you ordered from Rockauto.


I couldn't find a Beck-Arnley MAP listed for the 1992 Isuzu Impulse RS (I've found this to be the most reliable Rockauto cross reference) but there is a Beck-Arnley #1580380 listed against the 1992 Isuzu Impulse XS. Now the XS is normally aspirated so I suspect that this is a 1 bar MAP sensor and therefore no good for a turbo engine. Also, as yours is marked as an MTE-Thomson 7120, I guess Beck-Arnley and/or Rockauto aren't being 100% honest.... Now, on page 193 of the MTE-Thomson catalogue there are a few cars listed under the 7120 MAP sensor, none of which I recognise as being turbo assisted so I think your MAP that doesn't work is definitely a 1 bar sensor.

Further checking of the Rockauto catalogue shows that the 1991 Isuzu Impulse RS lists some of the same MAP sensors as the XS (including the Beck-Arnley #1580380) so it certainly looks like Rockauto have screwed up and hopefully they will sort you out. I've taken screen dumps and saved them below in case you get any problems with them!

Rockautp 1991 Isuzu Impulse RS MAP.gif

Rockautp 1992 Isuzu Impulse RS MAP.gif

Rockautp 1992 Isuzu Impulse XS MAP.gif

[PECKHS]

tks Geoff, I was thinking the same ...
however, I have again ordered the Delphi PS10075 11B1 from rockauto, and it just arrived yesterday. the thing is, the model was printed on a sticker, and after what happened, i'm not so sure if it is the correct item
these are the pics





has anyone gotten the delphi from them before, and can anyone verify if this looks similar?

the elan is in the shop fixing the hood elastic and variuos seals. will pop this in when it's back. hopefully all goes well after

cheers

peck