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Discussion Starter #1
My '98 engine is cutting out at various times under load. It will suddenly lose power, like there is no ignition. It will come back once you let off the gas. I checked the codes and the number P1106 popped up. Could this particular code be pointing to this problem? Can this code be caused by overboosting? Could overboosting cause such an abrupt reduction in power by the ECU trying to protect the engine?
 

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Wingless Wonder
1988 Esprit Turbo
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That code relates to the MAP sensor. Generically:

P1106 Description

The Barometric Pressure (BARO) sensor is built into the Engine Control Module (ECM) and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the Manifold Absolute Pressure (MAP) sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a code is stored.
Could the wires have been pinched/abraded if the intake manifold was removed in the past?
 

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Actually the code is a rationality check between the MAP and BARO sensors. Could be a problem with either or both. You should have a check engine light. Are there any other codes? Check your fuel pressure.
David Teitelbaum
 

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Discussion Starter #4
Fuel pressure is fine. I purchased a new MAP sensor but didn't get a chance to try it out. I now have an ECU issue. I'll outline it in another post. Ugh...
 

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Before buying and throwing parts at the problem, a little diagnosis is in order. You should at least try to see what the values are that the ECU is seeing from the MAP and BARO sensors. I estimate more than 1/2 the time problems like this turn out to be wiring or connector problems. Before you start blaming the ECU, does it have the HTU software? If not, it should be sent back to Lotus USA and have it's firmware updated.
David Teitelbaum
 

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Discussion Starter #6
I wasn't blaming the ECU. I mentioned the ECU because I ran into a problem with it. I have the PUK race chips installed, using their installation where you solder sockets onto the board to hold their custom chips. In my diagnostic attempt, I decided to go back and try the stock chips to see if my problem happened to be with the new chips. In doing so, the ECU stopped responding. That's why responded in my post the way I did. After many a panicked days, I was able to trace down that issue to the socket leads were pushed into the sockets too far. After fashioning a tiny tool to carefully pry them forward, all is back working.

That all being said, I tend to agree that it's likely a bad wire or connection. How do I go about getting readings from the MAP and Baro sensors? I'm guessing the MAP may be able to be read through a decent OBDII? But I'm not sure how I'd go about reading the on-board Baro sensor?
 

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Any good scanner should be able to show you the values from all of the sensors. I am most familiar with the Tech 1 but you should be able to see what is going on with Freescan or Esprimon or any other good scanner. Because you are failing the rationality check, the place to start is to see at idle what the readings are on the MAP and BARO sensors. The ECU is probably upset because it is seeing the same readings from both and at idle the MAP should be lower than the BARO (vacuum in the manifold) against atmospheric pressure for the BARO. As for the HTU, forget about it, Lotus USA will not touch an ECU that has been socketed or chipped. About the chip being inserted "too far", sounds like the correct socket was not installed for the chip. Maybe clip the leads on the chip so this can't happen again. As so often happens, the first instinct is to blame the ECU when it most often is not. When the ECU wakes up it performs internal rationality checks and if it starts up it means it passed them all and is working. Again, the most common problem is wiring or connectors to the ECU followed by a malfunctioning sensor. At this point you should have a good scanner, multi-meter, and manual to trouble-shoot both sensors and the wiring to the ECU. First step is to perform a visual inspection of the wiring and connectors associated with the sensors, concentrating on the MAP sensor. Be alert, often during a visual inspection you may find other things that you weren't even looking for! Sometimes a ground wire for a sensor is left loose, sometimes the plugs for similar sensors are mixed up, wrong sensor for the car, wires can get pinched, connectors inside of plugs back out or get bent, all kinds of weird and unusual things. If you pull a connector apart and see droplets of water, corrosion, dirt, etc, take note.
David Teitelbaum
 

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Discussion Starter #8
Good advice. I very much believe the problem is some loose wire or bad ground somewhere.

As far as the HTU upgrade, it's not necessary. The chips from PUK act as a car with the HTU during normal driving, but then acts as a Red Race car when the throttle is depressed past 40%.
 
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